Question

Two number cubes are rolled, one after the other. each number cube lands on a digit, 1-6. let event a be that the first number cube lands on an odd number. let event b be that the sum of the rolls of both number cubes is greater than 8. what is the exact value of p(a|b)

Answer 1

The probability is 2/5 or 40%.

First, there are 10 different rolls that have a sum that is greater than 8.

Second, only 4 of them start with an odd number.
3 - 6
5 - 4
5 - 5
5 - 6

So the probability is 4 out of 10 or 2/5.