Question

Kay incorrectly measured a window as 21 inches wide. The actual width was 24 inches. What was the percent error of case measurements? A. 12.5% B. -12.5% C. 87.5% D. -87.5%

Answer 1

the error difference is simply 24 - 21 = 3.

now, if we take 24(corrected value) to be the 100%, what's 3 off of it in percentage?

`\begin{array}{ccll} amount&\%\\ \cline{1-2} 24 & 100\\ 3& x \end{array} \implies \cfrac{24}{3}~~=~~\cfrac{100}{x} \\\\\\ 8 ~~=~~ \cfrac{ 100 }{ x }\implies 8x=100\implies x=\cfrac{100}{8}\implies x=12.5`