Infogain Interview Question

This is a famous probability puzzle in which you have to choose the correct answer at random from the four options below.

Can you tell us whats the probability of choosing correct answer in this random manner.

1) 1/4
2) 1/2
3) 1
4) 1/4

1 comment:

  1. choosing at random from four options = 25% chance of guessing correctly.
    25% = 1/4.
    1/4 appears in two of the four answer choices; prob(A) + prob(D) = 1/4+1/4 = 1/2
    so at random, you have a 1/2 or 50% chance of choosing 1/4 as the correct answer, so 1/2 is a valid correct answer choice if you were guessing correctly. So, choosing answer choice 1,2, or 4 would yield a correct answer. This means that you have all correct answer choices, so answer choice 3 is also valid. All are correct, but answer choice 3 is the best answer