Math CentralQuandaries & Queries


Question from Corrine:

When I am shopping for clothing that is for sale, the advertisement may say the item is 30% off. The original price was $70. How much would it now be? (how do I figure that out?) Thank you!


Hi Corrine,

30% is $\large \frac{30}{100} \normalsize = 0.30$ so 30% of $\$70$ is

\[0.30 \times \$70 = \$21.\]

Hence the price is reduced by $\$21$ so the sale price will be

\[\$70 - \$21 = \$49.\]

Another way to look at this problem is to notice that $100\% - 30\% = 70\%$ and hence after a 30% reduction you pay 70%. Thus the sale price is

\[0.70 \times \$70 = \$49.\]


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