Bloomberg LP Interview Question for Financial Software Developers






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7
of 7 vote

a) 1/3 * 1/3 * 1/3 <- prob of picking a red ball each time is 1/3
b) 1 * 2/3 * 1/3 <-- first time it doesnt matter what you pick, second time, it should be one of the other colors which u hadnt picked first time. similarly 3rd time.

- Anonymous November 10, 2009 | Flag Reply
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0
of 0 votes

correct

- hehe April 13, 2010 | Flag
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0
of 0 votes

ouch, corrected the wrong answer

- hehe April 13, 2010 | Flag
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1
of 1 vote

a) 1/27
b) 1 * 2/3 * 1/3 = 2/9

Final answer.

- Nix November 22, 2009 | Flag Reply
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0
of 0 votes

confirm 1/27 and 2/9.
6/27 applies for the case ball needs to be in that order.

- henry January 21, 2010 | Flag
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0
of 0 votes

You do realize that 6/27 = 2/9, right?

- Anonymous February 09, 2010 | Flag
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0
of 0 votes

LOL henry is sucha stud.

- Anonymous July 25, 2011 | Flag
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1
of 1 vote

If you pick 3 balls, these are your possible combos:
YYY
BBB
RRR
RRB
RRY
BBR
BBY
YYB
YYR
YBR

Total ten combinations. Since picking one ball does not affect the probabilities,
all this combos have the same probability: 1/10

- vadimrok May 11, 2010 | Flag Reply
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0
of 0 votes

I too think in this way..

- code bug May 16, 2010 | Flag
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0
of 0 votes

vadimrok, you've missed (RBY) and many others.
Overall, there are 27 possible combinations - 3^3.
First case: only one of them (RRR) is suitable - 1/27
Second case: six are suitable - 6/27, which is also 2/9.

- Anonymous June 05, 2010 | Flag
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0
of 0 votes

rby and ybr are same

- lol August 21, 2010 | Flag
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0
of 0 votes

To anonymous: it's 27 possible permutations, not combinations.

To lol: You need all the permutations to calculate the probability, but since the second question didn't specify the ordering, you need to take every combination of red, yellow and blue (there are 6) to determine how many of the 27 ways they could have been selected.

- Frank January 30, 2011 | Flag
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0
of 0 vote

i think 1st answer is correct by anonymous...
but i am jus wondering u shud have asked the total number of red,blue and yellow balls in the bag...

- Anonymous November 11, 2009 | Flag Reply
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0
of 2 vote

first one is 1/27
second one 6/27

there are in total 3^3 ways in which 3 balls can be picked up...
in second case we have 1 of each and different ways we coudl have picked it up is 3!
and hence it is 6/27 which first is obvious there is only a singel way we could have picked up 3 red balls

- Samip November 18, 2009 | Flag Reply
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0
of 0 vote

Answer by Nix is correct . For part 2 , the explanation provided by the first anonymous poster is correct

- Mandar January 27, 2010 | Flag Reply
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0
of 0 vote

pat 2 should be 4/9
As: (1/3 * 2/3 * 2/3 ) + (2/3 * 1/3 * 2/3 ) + (2/3 * 2/3 * 1/3 )
= 3 *(4 / 27 )
= 4/9

- Anonymous February 21, 2010 | Flag Reply
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0
of 0 vote

part 2 should be 4/9
As: (1/3 * 2/3 * 2/3 ) + (2/3 * 1/3 * 2/3 ) + (2/3 * 2/3 * 1/3 )
= 3 *(4 / 27 )
= 4/9

- Anonymous February 21, 2010 | Flag Reply
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0
of 0 vote

don't argue with me anymore: 1/27 and 2/9
suppose N red N blue and N yellow. then the first case:
p=(N 3)/(3N 3)=N(N-1)(N-2)/3N(3N-1)(3N-2), because N is large enough, do the lim operation, then it's 1/27

similarly, the second case: p = (N 1)*(N 1)*(N 1)/(3N 3)
= N^3/(3N*(3N-1)*(3N-2)/6)
limp= 6/27=2/9

never do analysis, math illustrates everything! How are you sure your analysis is correct, men?

- beyondfalcon August 27, 2010 | Flag Reply
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0
of 0 votes

He is right, try to use a tree and illustrate all the cases.

- ZhenZhangQD@googlemail.com January 05, 2011 | Flag
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0
of 0 vote

since the number of balls is large enough, the answer for b is also 1/3*1/3*1/3

- Anonymous January 09, 2011 | Flag Reply
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-1
of 1 vote

1) 1/3*1/3*1/3 =1/27
2) (3*1/3)*(2*1/3)*(1*1/3) =6/27
means for selecting red ball we have 3 options and for selsetcting blue ball we have 2 options ,for yellow we have only one option
Thanks
Vipin

- vipin.technocrat November 20, 2009 | Flag Reply
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-1
of 1 vote

1/3*1/3*1/3 for both a and b.

- sheshu November 07, 2010 | Flag Reply
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-1
of 1 vote

this ones correct

- hehe April 13, 2010 | Flag


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