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 Question from Kenneth: Hello: If a sales tax of 7% is placed on every $\$1.00$of merchandise for sale, is it correct to indicate the tax as 7%/ per$\$1.00$ or $7\%/\$1.00?$If the calculation is expressed as$7\%/\$1.00 \times \$5.00,$the tax is not$\$0.35$ but 0.35. Is a tax rate of 7% incorrectly represented as $7\%/\$1.00$since the dollar unit cancels from the multiplication? I thank you for your reply. Hi Kenneth, 7% is a unitless number, it is just another way of writing$\frac{7}{100}$or$0.07.$If a tax is 7% then the tax on$\$5.00$ is $0.07 \times \$5.00 = \$0.35$ as you observed in your question. The expression $\frac{7%}{\$1.00} = \frac{0.07}{\$1.00} = 0.07$ with units of one over dollars. This is not what you want.

You might say the tax is 7 cents per dollar which is $\frac{\$0.07}{\$1.00} = 0.07$ or 7%.

I hope this helps,
Penny

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