Question

The cost of the meal was 50 she left a $9 tip what was the percent of the tip

Answer 1

18% is the % of the tip

Answer 2

if we take 50 to be the 100%, what is 9 off of it in percentage?

$\bf \begin{array}{ccll} amount&\%\\ \cline{1-2} 50&100\\ 9&x \end{array}\implies \cfrac{50}{9}=\cfrac{100}{x}\implies x=\cfrac{9\cdot 100}{50}\implies x=18$