Question

The price of lettuce was $1.25 one week and $1.50 the next week.  Find the percent of increase.

Answer 1

So the lettuce went up by 0.25 or 25c, now, if we take 1.25 to be the 100%, how much is 0.25 in percentage off of it?

$\bf \begin{array}{ccllll} amount&\%\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 1.25&100\\ 0.25&x \end{array}\implies \cfrac{1.25}{0.25}=\cfrac{100}{x}\implies x=\cfrac{0.25\cdot 100}{1.25}$