Question

Robert weighs 180 pounds. He decreased his weight by 10% two months later. How much does he weigh after those 2 months? Show your work.

Answer 1

To determine how much is some percentage of a given amount, we divide this amount by 100 and then we multiply it by the number of the percentage we are looking for.

If Robert decreased his weight by 10%, it means that he weighs 90% of the original value. And to find 90% of his weight, we need to divide it by 100 and multiply by 90, as follows:

`\begin{gathered} W_(new)=W_(old)\cdot(90)/(100)=180\cdot(90)/(100)=1.8\cdot90 \\ \\ W_(new)=162\text{ pounds} \end{gathered}`Robert weighs 162 pounds.