Greg weighed 140 pounds. On his diet he lost 15 pounds. What was the percent of decrease in Greg's weight?

Well first you want to find out how much he weighed after his diet.

140-15 = 125

Next you want to take that and divide it by 140

125/140 = 0.8928571

To make it a percent multiply by 100

0.8928571*100 = 89.28571

Subtract from 100

100-89.28571 = 10.71249

He had a 10.71249% decrease in weight