Question

$42 is what percent of $50?

Answer 1

If  we take 50 to be the 100%, what's 42 in percentage?

well    $\bf \begin{array}{ccllll} amount&\%\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 50&100\\ 42&x \end{array}\implies \cfrac{50}{42}=\cfrac{100}{x}$

solve for "x"

Answer 2

42 dollars is 84% of $50