## Bloomberg LP Interview Question for Financial Software Developers

Country: United States
Interview Type: Phone Interview

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28
of 28 vote

it's simple:
take 1 apple from box 1, 2 apples from box 2 ... 10 apples from box 10

put all on scale, say it shows XX.Y pounds
look at Y (fractional part).
if it's 0, it's box 10
1 - box 9
2 - box 8
...
9 - box 1

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0
of 0 votes

Smart!

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0
of 0 votes

Thanks dude, this is the correct answer

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0
of 0 votes

The question specifically states that you don't have a scale.

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0
of 0 votes

@Second Anonymous: he meant "digital weight". There is no comparison of weights, only an absolute number, so this solution is correct.

This is probably not the only possible correct solution, but it certainly is correct.

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0
of 0 votes

Nice

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0
of 0 votes

it is correct

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2
of 2 votes

a little modification:
take 1 apple from box 1, 2 apples from box 2 ... 9 apples from box 9. That's it.

no need to take any apple from box 10.

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0
of 0 vote

``````Assign a number to every box say 1-N.
Take i apples from box i for measurement.
You will end up in [{N x (N+1) / 2} - {j x 0.9}] pounds.
Since you know N, calculate for j, which is the faulty box!``````

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0
of 0 votes

should be [{N x (N+1) / 2} - {j x (1 - 0.9)}]

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0
of 0 vote

well done amustea!!!!

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0
of 0 vote

One step solution:
1. Label boxes 1- 10.
2. Pick 1 apple from 1st box, 2 apples from 2nd box,.....10 apples from 10th box.
3. If all were good, their weight should add up to 1^2 + 2^2 + .....+10^2 = n.(n+1).(2n+1)/6 = 385.
4. Now measure the actual weight A.
5. (385 - A)*10 is your answer.

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0
of 0 vote

What happens if there are less than 55 (1+2+....10) apples in total in all the boxes ?

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0
of 0 vote

I have 1 solution if it was a weighing scale:
1) Take 1 apple from 1 box
2) Divide 10 apples in 4 groups of 3-3-3-1
3) Check each group on weighing scale
4) It is done in a single step

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-1
of 1 vote

Scrutinize all the other apples in all the boxes.The bad apples might look bad, smaller, wrinkled, smell off, dark patches ... pick the worst looking one from that box that look "terrible" and another from any box, that looks OK. Feel them (to be convinced) and weigh the one that looks bad. Use all the senses to judge, and the scale to verify.

We are comparing apples to apples and a tenth of a pound off is not negligible.

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-1
of 1 vote

One step solution:
1. Label boxes 1- 10.
2. Pick 1 apple from 1st box, 2 apples from 2nd box,.....10 apples from 10th box.
3. If all were good, their weight should add up to 1^2 + 2^2 + .....+10^2 = n.(n+1).(2n+1)/6 = 385.
4. Now measure the actual weight A.
5. (385 - A)*10 is your answer.

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0
of 0 votes

If all were good, their weight should be 1+2+3+4+5+6+7+8+9+10=55

Thus should be (55-A)*10

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0
of 0 votes

what you say is actually 10 steps (sort of smartly merged into one big step )

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0
of 0 votes

the solution should be done in 1 step. in your case it is n number of steps where n is no. of apples

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0
of 0 votes

What do you define as a step? Number of movements you make? He has assumed a step means reading once on the digital scale.

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0
of 0 votes

its really one step :)

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0
of 0 votes

its really 10 step :(

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