Question

A body builder consumed 5,600 calories yesterday. Today, he consumed 4,200 calories.
What is the percent decrease in number of calories consumed? Round to the nearest percent.

Answer 1

well, the difference from 5600 to 4200 is 1400.

If we take 5600 to be the 100%, how much is 1400 off of it in percentage?

$\begin{array}{ccll} amount&\%\\ \cline{1-2} 5600&100\\ 1400&x \end{array}\implies \cfrac{5600}{1400}=\cfrac{100}{x}\implies 4=\cfrac{100}{x} \\\\\\ 4x=100\implies x=\cfrac{100}{4}\implies x=25$