Question

Suppose that you roll two dice and don’t get to look at the outcome. Your friend looksat the outcome and tells you honestly that at least one of the dice came up 6. What isthe probability that the sum of your two dice is 8?

Answer 1

2/11

Explanation:

We have to calculate this by

p(B nA)/p(A)

= We have A¹ to be that none of the die roll gives us 6

P(A¹) = 5/6²

P(A) = 1 -5/6²

= 11/36

BnA = one die being 6 and summation being equal to 8

= BnA = (6,2)(2,6)

= P(BnA) = 2/36

Therefore we have (2/36)/(11/36)

= 2/11