Jane Street Interview Question

No unexpected question. Question: 37^2 = ? Paint a white cube red. Divide it into 27 same small cubes. Pick one small cube randomly and roll. What's the probability of all 5 faces you can see is white?

Interview Answers

Anonymous

Oct 19, 2013

The rolled cube needs to be either the inner cube or one of the six face centres. answer = (1/27)*(1) + (6/27)*(1/6) = 2/27

6

Anonymous

Jan 14, 2014

for the 27 small cubes, the number of "leagal cubes" is - 6, with one face colored red - 1, with all faces white So the probability is 1/27 + (6/27) * (1/6) = 2/27

1