A pair of dice are tossed. What is the probability that doubles are rolled, given that the sum on the two dice is less than 10?

Answer 1

Ways to get < 10: total ways - ways to get 10, 11, 12 = 36 - (3 + 2 + 1) = 30 ways

Doubles under sum of 10: (1,1) (2,2) (3,3) (4,4) -> 4 ways

So, probability = 4/30

Bayes theorem could be used for a more formal presentation.