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.
I have a simple but slightly time consuming way of doing this. Find 30% of 100 double it and then find 30% of 25, add the two together... In this case 60 + 7.5. After you do that subtract that number from 225. So subtract 67.5 from 225 and there is your answer. Your answer is 157.5
