Question

What is the probability that the product of two dice is greater than
15 on two separate rolls?

Answer 1

25/324

Explanation:

Make a table of possible products:

`\left[\begin{array}{ccccccc}&1&2&3&4&5&6\\1&1&2&3&4&5&6\\2&2&4&6&8&10&12\\3&3&6&9&12&15&18\\4&4&8&12&16&20&24\\5&5&10&15&20&25&30\\6&6&12&18&24&30&36\end{array}\right]`

Of the 36 results, 10 are greater than 15.

The probability the product is greater than 15 on a single roll is 10/36 = 5/18.

The probability the product is greater than 15 on two rolls is (5/18)² = 25/324.