Question

One year, the population of a city was 137,000. Several years later it was 117,820. Find the percent decrease.

Answer 1

well, the decrease was 137000 - 117820 = 19180.

now, if we take 137000(origin amount) to be the 100%, what's 19180 off of it in percentage?

`\begin{array}{ccll} amount&\%\\ \cline{1-2} 137000 & 100\\ 19180& x \end{array} \implies \cfrac{137000}{19180}~~=~~\cfrac{100}{x} \\\\\\ \cfrac{ 50 }{ 7 } ~~=~~ \cfrac{ 100 }{ x }\implies 50x=700\implies x=\cfrac{700}{50}\implies x=14`