



 
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,  


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