## Basic College Mathematics (9th Edition)

We provide examples of writing fractions as percents and percents as fractions: Fraction as percent: To convert $\frac{1}{2}$ to a percent, set up a proportion with $\frac{p}{100}$: $\frac{1}{2}=\frac{p}{100}$ Then cross-multiply: $1*100=p*2$ And solve for $p$: $p=100/2=50$ Thus $\frac{1}{2}$ as a percent is $50\%$. Percent as fraction: To convert $40\%$ to a fraction, write it as a fraction with 100 in the denominator: $40\%=\frac{40}{100}$ Next, simplify the fraction: $\frac{40}{100}=\frac{20}{50}=\frac{2}{5}$ Thus $40\%$ as a fraction is $\frac{2}{5}$. (Alternatively, one can use the table at the end of this section to convert common percents/fractions.)