Question

William bought Wiggit stock at 15.125 and sold it for 18. What was the percent of increase?

Answer 1

So from 18 to 15.125 is 2.875, namely their difference.

now, if we take 15.125 to be the 100%, what is 2.875 off of it in percentage?

$\bf \begin{array}{ccll} amount&\%\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 15.125&100\\ 2.875&p \end{array}\implies \cfrac{15.125}{2.875}=\cfrac{100}{p}\implies p=\cfrac{2.875\cdot 100}{15.125}$