Basic percentage calculations

Statement

Compute: (a) what is $12\%$ of $75$; (b) what percentage of $80$ is $28$; (c) $54$ is $45\%$ of which number?

Solution

(a) $12\%$ of $75$ is $\dfrac{12}{100}\cdot 75 = 0.12 \cdot 75 = 9.$

(b) The percentage is $\dfrac{28}{80} = 0.35 = 35\%.$

(c) If $54$ is $45\%$ of the number $N$, then $0.45\,N = 54$, so $N = \dfrac{54}{0.45} = 120.$

$\boxed{9 \ ;\quad 35\% \ ;\quad 120}$