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Frodo
Junior Artist Username: Frodo
Post Number: 423 Registered: 11-2009 Posted From: 219.64.65.109
Rating:  Votes: 1 (Vote!) | | Posted on Wednesday, May 05, 2010 - 03:19 pm: |
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Calvin : good one. the key thing to realise is that for a given set of 6 digits, there is only one way of arranging them in a descending order or non-descending order. same holds true obviously for ascending or non-ascending. anyway for non descending, no repetition of digits allowed, so it is just choosing 6 digits out of 10, so = 210 (you dont have to worry about digits numbers starting with zero, because descending order means zero will always end at the units place. for descending, the way to pick 6 digits out of 10 possible from 0-9 to form a 6digited number with any number of repitions, is given by what vjavasi was suggesting : let x0 be no. of zeros and x1 be no of 1s and so on then the answer for above is given by the no. of non-negative integer solutions to x0+x1+x2.....+x9 = 6. the answer for that is 15C6. vjavasi @ 10:31: the answer to that is (n+m-1)C m . if you are interested that is an interesting problem to solve too. Calvin: in the problem it states the guy is stuck in the 1st ditch. so F(2) = 1, F(3) = 2 and we need to find F(100) which equals fib(100). if you choose to call the 1st ditch 0th, then since there are 100 ditches only, you have to find F(99). anyways it is just a matter of semantics, i guess Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2289 Registered: 11-2009 Posted From: 117.195.206.153
Rating: N/A Votes: 0 (Vote!) | | Posted on Wednesday, May 05, 2010 - 11:45 am: |
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Calvin:
excellent bro....you got it |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2288 Registered: 11-2009 Posted From: 117.195.206.153
Rating: N/A Votes: 0 (Vote!) | | Posted on Wednesday, May 05, 2010 - 10:49 am: |
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sorry it's 10C1+5*10C2+7*10C3+8*10C4+5*10C5+10C6 -1 |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2287 Registered: 11-2009 Posted From: 117.195.206.153
Rating: N/A Votes: 0 (Vote!) | | Posted on Wednesday, May 05, 2010 - 10:31 am: |
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Frodo:
is it 10*10C1+5*10C2+7*10C3+8*10C4+5*10C5+10C6 -1 i am trying to evaluate possible six digit number combinations using 1,2,3,4,5,6 digits out of ten...one is deducted to remove 6 digit number formed by zero(oooooo)... if there is a general formula to get number of possible integer solutions for an equation of form x1+x2+.....+xn = m then we can generalize the above solution I have to catch flight to US, i will work on this later |
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Calvin
Junior Artist Username: Calvin
Post Number: 39 Registered: 03-2008 Posted From: 66.129.224.36
Rating:  Votes: 1 (Vote!) | | Posted on Wednesday, May 05, 2010 - 10:23 am: |
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Looks like f(k) = 5c(6-k) First lets see strictly descending - selection of 6 digits from 10, and arrange them in any order. There is only arrangement possible that causes it to have strictly descending order for these 6 digits. From this order, if we swap any 2 places to create a new number, its no longer strictly descending order.. so the answer for that is 10c6 Now extending that to descending- where a(i) >= a(i+1) this can also be written as a(i) = a(i+1) = a(i+2) ... = a(i+k-1) > a(i+k) that is if you pick unique digits in the number, they will always be in strict descending order. So in descending - the number of unique digits in the number can be from 6 to 1. When the unique digits is 6, its case 1. 10c6 Now create 6 digit numbers with 5 unique digits. select 5 digits - 10c5. Now we need to fill the position of 6th digit which is going to be a duplicate of one of the 5 digits selected.. for example - 654322 or 654432 or 654332.. the duplicate can occur at any place from 1 to 6. Now there is one place to fill with a digit selecting from 5= 5c1 therefore the number of 6-digit numbers with 5 unique digits = 5*10c5 now for 4 digits = pick 4 unique digits , now we have 2 places to fill. This is where I got wrong earlier.. This again recursively - (not sure if it can be done much simpler way) in the 2 places, there can be 1 digit or 2 digits... this can be done in 4c1 + 4c2 = 5c2 For 3 unique digits - 3 duplicate places to fill - 3c1 + 3c2* 2c1 + 3c3 = 5c3 For 2 unique digits - 4 duplicate places to fill - 2c1 *1c1*1c1*1c1 + 2c2 * (2c1+2c2) = 5c4 for 1 unique digit - 5 duplicate places to fill - 1c1 * 1c1*1c1*1c1*1c1 = 5c5 F(2) = 2, considering he can reach 2nd ditch in 2 1-hops or 1- 2hops if he starts from 0th ditch (no ditch) |
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New_user
Side Hero Username: New_user
Post Number: 9918 Registered: 02-2008 Posted From: 174.136.55.4
Rating: N/A Votes: 0 (Vote!) | | Posted on Wednesday, May 05, 2010 - 08:20 am: |
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At any given ditch, other than 100th, only 2 choices untayi. So answer 99x2 + 1 choice at 100th ditch = 199 anukuntunna. Khan Dada - Chiru. Manikyam - Pans. |
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Frodo
Junior Artist Username: Frodo
Post Number: 420 Registered: 11-2009 Posted From: 115.117.197.7
Rating: N/A Votes: 0 (Vote!) | | Posted on Wednesday, May 05, 2010 - 06:31 am: |
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calvin @ 9:32 : that expression does not evaluate to the right answer. Could you explain what you mean by selection of digits with duplicates from 1 to 6? also @ 8:49 F(2) = no of ways to get to ditch 2 from ditch 1 = 1way only 1hop. so F(2) = 1 and not 2, right? Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Calvin
Junior Artist Username: Calvin
Post Number: 38 Registered: 03-2008 Posted From: 66.129.224.36
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 09:32 pm: |
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Nah.. got it wrong again - Found to be wrong when I was driving home from office.. Descending = Summation of f(k)* 10ck -1 for k=6 to 1. f(k) = k^(6-k) I think I got it right this time.... its selection of digits with duplicates from 1 to 6. |
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Calvin
Junior Artist Username: Calvin
Post Number: 37 Registered: 03-2008 Posted From: 66.129.224.36
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 08:55 pm: |
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correction - Descending = 10 c6+ 5*10c5+ 4*10c4 + 3*10c3+ 2 *10c2+ 1*10c1 - 1 (we need to subtract the number with all zeros) |
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Calvin
Junior Artist Username: Calvin
Post Number: 36 Registered: 03-2008 Posted From: 66.129.224.36
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 08:49 pm: |
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strictly descending - 10c6 = 10c4 = 210 descending = 10c6 + 5*10c5 + 4*10c4 + 3*10c3 + 2 * 10c2 + 1*10c1 The other problem - should not it be 101 th term of fibonacci series as opposed to 100 th term? F(100) = F(99) + F(98) and F(2) = 2 In fibonacci = Fib(2) = 1 F(100) = Fib(101) |
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Frodo
Junior Artist Username: Frodo
Post Number: 416 Registered: 11-2009 Posted From: 59.161.177.142
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 07:04 pm: |
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no dude. unless my matlab programming is wrong, that expression is way off the right answer. your logic is obviously correct, but there is a line of thought, that will simplify the solution a lot. want to try another way of solving this? i dont know if this is much of a hint, but the answer can be expressed as nCr. Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2285 Registered: 11-2009 Posted From: 202.133.58.84
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 12:45 pm: |
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Frodo:dscending means a(i) >= a(i+1)
is it 9*10^5 - sigma of n (2(n^5+n^4+n^3+n^2+n) +(n^4*(9-n)+n^3*(9-n)^2+n^2*(9-n)^3+n(9-n)^4))+9^5 where n ranges from 1 to 9 , 9^5 is not included in the sigma, the logic behind this is for each decimal place i tried to find the count of numbers having bigger digits to the right or smaller digits to the left or bigger to the right and smaller to the left, subtracted the sum of these counts from number of six digit numbers...the last term 9^5 is to compensate for numbers that have higher digits to the right but starts with zero |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2284 Registered: 11-2009 Posted From: 202.133.58.83
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 11:19 am: |
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Frodo:anyway, back to the problem, tell me the logic for that 2nd part.
i am trying to subtract Frodo:anyway, back to the problem, tell me the logic for that 2nd part.
i want to subtract all possible combinations of digits that are greater to the right and lesser to the left for each decimal place for all possible digits from number of six digit numbers...the expression below just subtracts combinations of greater digits to the right from the number of six digit numbers...let me try for some more time to get the right expression |
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Thirtyplus
Junior Artist Username: Thirtyplus
Post Number: 417 Registered: 03-2009 Posted From: 174.103.243.218
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 11:14 am: |
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thread motham choosthe ardham ayindi.....order of jumping kooda teesukunnarani 2500 is when the order is not considered anyways TDP - TODU DONGALA PARTY
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Thirtyplus
Junior Artist Username: Thirtyplus
Post Number: 416 Registered: 03-2009 Posted From: 174.103.243.218
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 10:57 am: |
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101 - 2x where x = 1 to 50 answer - 2500 TDP - TODU DONGALA PARTY
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Frodo
Junior Artist Username: Frodo
Post Number: 415 Registered: 11-2009 Posted From: 59.161.177.142
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 10:30 am: |
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You are way off @ 9:29 but spot-on @ 9:35. what is your logic behind 9:29? oka concept grasp chesthe this problem has a straight forward solution, though it does need a not-so-beginner level combinatorial concept to get the eventual answer. The prof i mentioned used to give his prospective students this problem to see if they get that concept. the prof had the total works - caltech ph.d, total loner, talking to himself as he walks in the corridors, punching the walls in excitement, bachelor @ 45. i dont think he talked to any non- communications guy other than me. many a time we used to be the only 2 guys @ 3 in the morning and that was how we became friends.... anyway, back to the problem, tell me the logic for that 2nd part. Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2283 Registered: 11-2009 Posted From: 202.133.58.83
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 09:35 am: |
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Frodo:strictly descending means a(i) > a(i+1)
my answer is 210 for this ....what's the right answer |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2282 Registered: 11-2009 Posted From: 202.133.58.83
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 09:29 am: |
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Frodo:dscending means a(i) >= a(i+1)
9*10*10*10*10*10 -(8^5+7^5+6^5+5^5+4^5+3^5+2^5+1^5) -(9^4+8^4+........+1) -(9^3+.........+1^3) - (9^2+.........+1^2) -(9+8.....+1) |
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Frodo
Junior Artist Username: Frodo
Post Number: 414 Registered: 11-2009 Posted From: 59.161.177.142
Rating: N/A Votes: 0 (Vote!) | | Posted on Tuesday, May 04, 2010 - 01:23 am: |
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strictly descending means a(i) > a(i+1) dscending means a(i) >= a(i+1) Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2281 Registered: 11-2009 Posted From: 202.133.58.78
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 09:12 pm: |
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Frodo:when you do right to left, the answers are not correct.
sorry my answers are for numbers descending from lakhs to units, if strictly descending means difference between any two consecutive digits should be constant then my answer is 5, the numbers are 543210 654321 765432 876543 987654 if the difference between the digits need not be constant but digits can't repeat then answer is 210 which also includes the above five numbers. |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2280 Registered: 11-2009 Posted From: 202.133.58.78
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 08:57 pm: |
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Frodo:it is strictly descending or descending from lakhs positions to units. (left to right that is...) even when you do right to left, the answers are not correct.
strictly descending means difference between any two consecutive digits should be same right? |
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Frodo
Junior Artist Username: Frodo
Post Number: 413 Registered: 11-2009 Posted From: 115.117.204.188
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 02:24 pm: |
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it is strictly descending or descending from lakhs positions to units. (left to right that is...) even when you do right to left, the answers are not correct. Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2279 Registered: 11-2009 Posted From: 202.133.58.75
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 01:29 pm: |
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Vjavasi:if it is from right..it's 6
it's only 5 |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2278 Registered: 11-2009 Posted From: 202.133.58.75
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 01:28 pm: |
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Frodo:A) in strictly descending order
if it is from right..it's 6
Frodo:B) in descending order
from the right 5C5+6C5+7C5+8C5+9C5 = 1+6+21+56+126 = 210 |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2277 Registered: 11-2009 Posted From: 202.133.58.75
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 01:09 pm: |
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Frodo: ok google tells me F(100) = 354 224 848 179 261 915 075. and incidentally 354 224 848 179 261 915 075 / (2^50) = 314 614.866 so I was about 6orders of magnitude away in my calculation. thanks for the puzzle. If guys are interested here is a combinatorics problem that earned me 1000$ from a prof of mine. How many 6digited numbers have their digits A) in strictly descending order
from the left or right? |
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Frodo
Junior Artist Username: Frodo
Post Number: 412 Registered: 11-2009 Posted From: 115.117.204.188
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 12:30 pm: |
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ok google tells me F(100) = 354 224 848 179 261 915 075. and incidentally 354 224 848 179 261 915 075 / (2^50) = 314 614.866 so I was about 6orders of magnitude away in my calculation. thanks for the puzzle. If guys are interested here is a combinatorics problem that earned me 1000$ from a prof of mine. How many 6digited numbers have their digits A) in strictly descending order B) in descending order Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Frodo
Junior Artist Username: Frodo
Post Number: 411 Registered: 11-2009 Posted From: 115.117.204.188
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 12:19 pm: |
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" it is actually the 100 term of a fibanacci series..i,e the sum of the first 99 terms " 100th term is sum of only 99th and 98th term right, not all the 1st 99 terms. yes? Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Frodo
Junior Artist Username: Frodo
Post Number: 410 Registered: 11-2009 Posted From: 115.117.204.188
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 12:15 pm: |
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wait, the answer is F(100). right? i goofed up again. it is not sum of 1st 100 fibonacci terms, but just F(100). Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5620 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 12:08 pm: |
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Frodo:
it is actually the 100 term of a fibanacci series..i,e the sum of the first 99 terms and it is of the order 2^50 but not equal to it |
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Frodo
Junior Artist Username: Frodo
Post Number: 409 Registered: 11-2009 Posted From: 115.117.204.188
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 12:06 pm: |
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@ Der @ 8:11 is it the sum of the 1st 100 terms in the fibonacci sequence? I have no idea how to calculate that without a computer program..... is the answer right? if yes, how do you sum up the 1st 100 terms of the fibonacci? Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2276 Registered: 11-2009 Posted From: 202.133.58.74
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 11:15 am: |
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Der_schuler: Frodo: 2^50 ~ 1e15 seems right....there is a beautiful way to solve this with no combinatorics at all
i think number of possible combinations is greater than 2^50 |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2275 Registered: 11-2009 Posted From: 202.133.58.74
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 11:12 am: |
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Der_schuler:this is about right but for some integer change.
emi change avvali bro? |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5614 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 08:14 am: |
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Vjavasi:sorry it should be sum over 100-n(C)n where n ranges from 0 to 50
Yes. this is about right but for some integer change. But u are on the right track...keep persevering with that line of thought and see if u see some elegance in the way that terrible falling sum will surface into sum beautiful series?? |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5613 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 08:11 am: |
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Frodo:2^50 ~ 1e15
seems right....there is a beautiful way to solve this with no combinatorics at all |
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Frodo
Junior Artist Username: Frodo
Post Number: 408 Registered: 11-2009 Posted From: 115.117.251.42
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 06:15 am: |
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slumdawg: did we interact before. pardon me for being dense, too much stress on my grey-matter last 1month or so.... vjavasi : both your expressions are the same as the one i put up with k..... i think your is a more elegant and concisely put. Stig: another way to look at this is, getting 100 = no of ways to get to 99 + number of ways to get to 98. You can then keep going recursively as follows : number of ways to get to 99 = number of ways to get to 98 + number of ways to get to 97... similarly number of ways to get to 98 = number of ways to get to 97 + number of ways to get to 96... you can continue this series till you get number of ways to get to 2 which is equal to 2. I am not good with math jargon at undergrad level, but that might be some kind of recursive series..... this was my thought intuitively, but as usual my intuition led me to a monster but then this seems to qualify the only addition tag better than the combinatorial solution i mentioned in the morn.... i have to work on what that summation simplifies to.... provided we have confirmation that is the way to go.... later... Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Slumdawg
Junior Artist Username: Slumdawg
Post Number: 560 Registered: 04-2010 Posted From: 204.74.221.58
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 01:54 am: |
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Frodo:
Frodo kurrod how r u Sombabu |
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Frodo
Junior Artist Username: Frodo
Post Number: 407 Registered: 11-2009 Posted From: 115.117.251.42
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 01:44 am: |
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@ stig : forget that, i made an @ss of U and ME (i @SSUMEd something wrong). here is what i thought.... no. of ways = no of ways person can make 50 2hops and 0 1hops + no of ways person can make 49 2hops and 2 1hops + no of ways person can make 48 2hops and 4 1hops + no of ways person can make 47 2hops and 6 1hops + .................. + ........... + no of ways person can make 0 2hops and 100 1hops In short it is the summation of ways in which a person can make 50-k 2hops and 2k 1hops, with k ranging from zero to 50. to find the kth term, let us look at how many ways person can make 50-k 2hops and 2k 1hops. basic combinatorics ( guess i am violating the counting problem and/or only addition operator funda here), anyhow the number of ways that can be done = (50-k + 2k) C 2k which simplifies to (50+k) C 2k. therefore the answer should be summation of [ (50+k) C (2k) ] for k = 0 to 50. Hope i did not goof it this time around. There is another way of doing this, i will tell you that when i take my break from my next class. Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2274 Registered: 11-2009 Posted From: 202.133.58.71
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 01:32 am: |
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Vjavasi:it will be sum of m+n(C)m where m changes from 0 to 50
sorry it should be sum over 100-n(C)n where n ranges from 0 to 50 |
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Vjavasi
Side Hero Username: Vjavasi
Post Number: 2273 Registered: 11-2009 Posted From: 202.133.58.71
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 01:30 am: |
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let's say no of two hops is n no of one hops is m relation between n and m is m = 100 - 2n n could range from 0 to 50 so total number of combinations is 51 if you have to consider the order of jumping also then you have to look for different combinations for a given m,n it will be sum of m+n(C)m where m changes from 0 to 50 |
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Frodo
Junior Artist Username: Frodo
Post Number: 406 Registered: 11-2009 Posted From: 115.117.251.42
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 12:55 am: |
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by the way, this part of the question is very ambiguous : "As an example: U making 50 2 ditch hops is one way same with 100 "1 ditch hops" Do you mean 50 2ditch hops is one way of jumping and another way is 100 1 ditch hops? the way you worded it makes it sound like 50 2ditch hops is equivalent to 100 1 ditch hops. I am guessing you meant the former interpretation of mine, but can you elaborate? Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Stig
Side Hero Username: Stig
Post Number: 2169 Registered: 01-2010 Posted From: 67.80.101.77
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 12:54 am: |
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Frodo: the answer is 2^50 ~ 1e15. right?
Ela ?? ------- Only seven people have looked The Stig straight in the eyes. They are all dead now !!
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Frodo
Junior Artist Username: Frodo
Post Number: 405 Registered: 11-2009 Posted From: 115.117.251.42
Rating: N/A Votes: 0 (Vote!) | | Posted on Monday, May 03, 2010 - 12:49 am: |
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if i understand the question correctly and if i can trust my 8th grade math, the answer is 2^50 ~ 1e15. right? compliments to frodo, brickbats to 8th grade math prof! j/k, i had a totally nutty prof (that is what i will call him, he was just way too impatient to qualify as a middle-school teacher! all the students except me and 2 other friends of mine used to hate him with a vengeance! and we used to call him nattu) and by the time i finished 12th, i could crack math problems faster and more elegantly than him, but am yet to beat him in a game of chess. for good or bad, he made me the competitive bar-stud i am....... Dal tadka, dum-biryani and Deccan chargers - always no.1  |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5612 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 09:59 pm: |
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Maverick: did u purposefully misguide ppl here?
Didn't get u? Proline......well when I say there are 100 ditches then is it not implicit that they are unique?? |
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Maverick
Hero Username: Maverick
Post Number: 15898 Registered: 01-2008 Posted From: 24.1.171.91
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:19 pm: |
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Der_schuler:As an example: U making 50 2 ditch hops is one way same with 100 "1 ditch hops"
did u purposefully misguide ppl here? if u r in ditch1 and make a 2 ditch hop, u r in ditch 4..so u need only 25 2 ditch hops+ 1 more to passs 100 ditches??something like that..am i wrong? |
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Abcdefghij
Side Hero Username: Abcdefghij
Post Number: 7285 Registered: 02-2007 Posted From: 76.226.22.167
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:15 pm: |
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Der_schuler:agreed but there 1 other dimension...how are these 1 and 2 hops distributed per individual way??
are you saying starting 1hop, 49 2hops is different than 49 2 hops and 2 1 hops etc? |
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Hail_the_labour
Side Hero Username: Hail_the_labour
Post Number: 2148 Registered: 06-2008 Posted From: 75.185.82.44
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:11 pm: |
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Der_schuler:agreed but there 1 other dimension..
der: do you mean hops are not horizontal straight. if they are spread in rectangular,square,geometric fashion they 3rd dimension of cross-hopping will add more possible ways to my number series so my previous answer+extra possible ways is my revised answer |
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Proline
Side Hero Username: Proline
Post Number: 4509 Registered: 06-2008 Posted From: 173.3.73.246
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:11 pm: |
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Der_schuler:there are 100 ditches
if permutations/order does matter, then the problem will be stated as there are 100 distinct ditches or there are 100 ditches numbered from 1 to 100 etc and thats when the order does matter. ... |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5611 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:10 pm: |
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The only hint I can afford to give with out bleeding the life of the problem is that it is classic computer science problem |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5610 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:08 pm: |
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I never mentioned the word combinations or permutations, I posed this as a counting problem and it unless specified can't be classified as a combinatoric problem....its another issue that u can cast it as one |
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Tnmnm
Junior Artist Username: Tnmnm
Post Number: 6 Registered: 04-2010 Posted From: 199.71.214.205
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:08 pm: |
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Der_schuler:
correct annai. problem antha simple ga ledu naaku. manakekkaledu...correct answer kosam wait sestha. |
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Hail_the_labour
Side Hero Username: Hail_the_labour
Post Number: 2147 Registered: 06-2008 Posted From: 75.185.82.44
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:07 pm: |
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Der_schuler:not the right answer...gimme the line of attack
I understood the condition as any comnination of hops is allowed (1 or 2). best hop : 50 (2 ditches) worst hop: 100(1 ditch) any combination of hops will fall in between 50 to 100. ex. he can do 45 2 hops =90 + 10 1hops = 55 hops . like wise |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5609 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:07 pm: |
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Proline:
Hmm let me clarify...I said what are possible ways in which u can reach the 100th ditch...implicit to it is the assumption that intrinsic order is important |
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Proline
Side Hero Username: Proline
Post Number: 4508 Registered: 06-2008 Posted From: 173.3.73.246
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:05 pm: |
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Der_schuler:how are these 1 and 2 hops distributed per individual way??
order does not matter as per the quiz. so it does not matter how they are distributed ... |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5608 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:04 pm: |
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Proline: simple. you have to use only one addition for combining the ways: so let us start with 2hops. min two hops can be 0 and max can be 49 (as per the hint, 0 two hops combination and 50 two hops combination are the same so ignoring 50 two hop) 0 two hops + 100 1 hops same as 50 2 hops + 100 0 hops 1 two hop + 99 1hops and so on 49 two hops + 2 1 hops so total combinations = 50
agreed but there 1 other dimension...how are these 1 and 2 hops distributed per individual way?? |
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Proline
Side Hero Username: Proline
Post Number: 4507 Registered: 06-2008 Posted From: 173.3.73.246
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:03 pm: |
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note: order does not matter (as it is not given in the quiz, so i can safely ignore the permutations) ... |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5607 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:01 pm: |
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Hail_the_labour:
well thats not a difficult series it is just (50*51/2)+50 = 25*53 not the right answer...gimme the line of attack |
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Proline
Side Hero Username: Proline
Post Number: 4506 Registered: 06-2008 Posted From: 173.3.73.246
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 08:01 pm: |
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Der_schuler:elaborate please...I need to see ur line of reason??
simple. you have to use only one addition for combining the ways: so let us start with 2hops. min two hops can be 0 and max can be 49 (as per the hint, 0 two hops combination and 50 two hops combination are the same so ignoring 50 two hop) 0 two hops + 100 1 hops same as 50 2 hops + 100 0 hops 1 two hop + 99 1hops and so on 49 two hops + 2 1 hops so total combinations = 50 ... |
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Hail_the_labour
Side Hero Username: Hail_the_labour
Post Number: 2146 Registered: 06-2008 Posted From: 75.185.82.44
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:59 pm: |
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sum of series : starting 50,51,52...100 answers is : some thousand combinations |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5604 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:55 pm: |
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Proline:
elaborate please...I need to see ur line of reason?? |
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Abcdefghij
Side Hero Username: Abcdefghij
Post Number: 7284 Registered: 02-2007 Posted From: 76.226.22.167
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:51 pm: |
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50 |
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Proline
Side Hero Username: Proline
Post Number: 4504 Registered: 06-2008 Posted From: 173.3.73.246
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:50 pm: |
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inlcuding the hint, it will be 50 ways ... |
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Proline
Side Hero Username: Proline
Post Number: 4503 Registered: 06-2008 Posted From: 173.3.73.246
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:49 pm: |
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49 ways you can solve this (assuming the hint given is not considered in 49) is it correct ... |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5603 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:39 pm: |
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Tnmnm:naa calculation septhaa... 2x+1y = 100 eskunte... y=2x substitution sesthe...20 ways vathaayi...
The problem with this approach are many fold: 1.) the right hand side of the above equation is not 100 (why??) 2.) y= 2x is a false relationship (??) |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5602 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:36 pm: |
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Tnmnm:
Navvu endhukandi....remember einstein's quote, " if u think you have problems with math, rest assured as I have even bigger ones with it" answer to me is trivial, I am more keyed to how original u are in ur thoughts 20 is wrong |
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Tnmnm
Junior Artist Username: Tnmnm
Post Number: 5 Registered: 04-2010 Posted From: 76.73.2.10
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:35 pm: |
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naa calculation septhaa... 2x+1y = 100 eskunte... y=2x substitution sesthe...20 ways vathaayi... |
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Tnmnm
Junior Artist Username: Tnmnm
Post Number: 4 Registered: 04-2010 Posted From: 76.73.2.10
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:33 pm: |
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20 total possible ways aa annai? nenu maths la eek. navvukoka |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5601 Registered: 01-2009 Posted From: 68.46.21.1
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:33 pm: |
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Stig:
umm let me know how u arrived at this number...the answer is not the important thing but the process (49 tho is wrong) |
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Stig
Side Hero Username: Stig
Post Number: 2163 Registered: 01-2010 Posted From: 67.80.101.77
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:10 pm: |
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Der_schuler:
49 ?? ------- Only seven people have looked The Stig straight in the eyes. They are all dead now !!
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Slumdawg
Junior Artist Username: Slumdawg
Post Number: 526 Registered: 04-2010 Posted From: 204.74.221.12
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:03 pm: |
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Rakesh:4years intermediate and 3 times 10th class....sallagaa nokkesaav gaa aatini
resume mottam seppak tamud...sigguto sachi savam aipota Sombabu |
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Rakesh
Junior Artist Username: Rakesh
Post Number: 18 Registered: 04-2010 Posted From: 98.210.96.94
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 07:00 pm: |
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Slumdawg:6 ears lo complete sesesa
4years intermediate and 3 times 10th class....sallagaa nokkesaav gaa aatini |
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Slumdawg
Junior Artist Username: Slumdawg
Post Number: 525 Registered: 04-2010 Posted From: 204.74.221.12
Rating: N/A Votes: 0 (Vote!) | | Posted on Sunday, May 02, 2010 - 06:57 pm: |
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lekkallo eek.. donasion katti BA sesa....6 ears lo complete sesesa Sombabu |
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Der_schuler
Side Hero Username: Der_schuler
Post Number: 5600 Registered: 01-2009 Posted From: 68.46.21.1
Rating:  Votes: 1 (Vote!) | | Posted on Sunday, May 02, 2010 - 06:44 pm: |
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Super day recruiting ki monna variety scheme ettar.....people who came to interview are supposed to pose a question to the interviewer opposed to the normal way...the intent was to see whether people are active with their math/logic and also on how the prospects will make others think along with them when they are in the driving seats.. Oka hebrew university math undergrad kurrod ee question adigad nannu.... "Suppose there are 100 ditches and you are stuck in ditch 1 and need to go past the 100th ditch. Your physical capacity allows you to hop over 1 ditch or 2 ditches in one go i.e you can either make 50 "2 ditch hops" or 100 "1 ditch hops" or a combination of both. If you are allowed to solve the problem using only one arithmetic operation of addition, how do you calculate all the possible ways in which u can go past the 100 ditches?? As an example: U making 50 2 ditch hops is one way same with 100 "1 ditch hops" The time to solve this is 5-7 mins roughly |