Let X be the random variable representing the number
of coins that Matt set aside after three flips.

We have to run n from 0 to 100 and m from 0 to (100-n),
Find the binomial law, then compute the mean like this:

Hope this gives a hint.
Step-by-step explanation:
<h2>stay safe healthy and happy...</h2>
Divide by 4 to get 9 and a R of 2, then just put the remainder as the numerator, and you have 9 1/2 (simplified)