Question

A pair of fair dice is rolled and the sum of the numbers is noted. Determine the probability that one die resulted in a 5 given that the sum is 8.

Answer 1

Pairs whose sum is 8:
2 + 6, 3 + 5, 4 + 4, 5 + 3, 6 + 2 ( there are 5 pairs )
Pairs when one die is 5: 3 + 5, 5 + 3 ( 2 pairs )
P ( A ) = 2 / 5 = 0.4
Answer: The probability that one die resulted in a 5 given that a sum is 8 is 0.4 .