Multiply the numerators and denominators together. Keep the result fraction to the smallest possible denominator GCD(4, 15) = 1. It cannot further simplify the fraction result by canceling in the following intermediate step.
In other words, two fifths times two thirds equals four fifteenths.
There are 37 jelly beans so p for the first one is 27/37. That leaves 36 in the bag. So p for the second jelly bean is 10/36=5/18. The combine probability is 27/37×5/18=3/37×5/2=15/74.
