Question

you can warm up spaghetti on a gas range in 10 minutes you can warm up that same spaghetti in the microwave in 2 minutes find the percent of decrease in cooking time

Answer 1

So, from 10 minutes down to 2 minutes, the difference is 8 minutes.

if we take 10 to be the 100%, what is 8 off of it in percentage?

$\bf \begin{array}{ccll} amount&\%\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 10&100\\ 8&x \end{array}\implies \cfrac{10}{8}=\cfrac{100}{x}\implies x=\cfrac{8\cdot 100}{10}$