Question

the ratio of red cars to blue cars in a parking lot was 5:3. If there was 40 red cars how many blue cars were there?

Answer 1

there were 24 blue cars

Answer 2

$\bf \cfrac{red}{blue}\qquad 5:3\qquad \cfrac{5}{3}~\hspace{8em}\cfrac{40}{x}=\cfrac{5}{3}\implies \cfrac{40\cdot 3}{5}=x\implies 24=x$