Two dice are thrown. Find the probability that the numbers appeared to have a sum of 8 if it is known that the second dice always exhibits 5.
Answer & explanation
Correct answer: option 4
A: Sum of the numbers is 8, i.e. {(2,6), (3,5), (4,4), (5,3), (6,2)} B: the second die always exhibits 5, i.e. {(1,5), (2,5), (3,5), (4,5), (5,5), (6,5)} A ∩ B= {(3,5)}
n(A ∩ B) = 1
n(A) = 6
$ P = \frac{1}{6} $