Is my answer correct?
What is the probability of throwing a sum of 15 on three rolls of a fair die if the first roll was a 4?
1/36.
Thanks.
You are close.
Given that the first roll is a 4, your next two rolls must add to 15-4 = 11.
There are actually two ways to get 11: 5 & 6, and 6 & 5.
So the probability is 2/36, or 1/18.