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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.

Robert weighs 180 pounds. He decreased his weight by 10% two months later. How much-example-1
User Littlee
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1 Answer

29 votes
29 votes

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.
User Konrad Kiss
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