Question

A standard bathtub holds 70 gallons of water. On average, it takes 7 and 1/2 minutes to drain a bathtub. How many gallons of water go down the drain each minute?

Answer 1

`\bf \begin{array}{ccll} \stackrel{drain}{minutes}&\stackrel{bathtub}{gallons}\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 7(1)/(2)&70\\ 1&x \end{array}\implies \cfrac{7(1)/(2)}{1}=\cfrac{70}{x}\implies \cfrac{(15)/(2)}{(1)/(1)}=\cfrac{70}{x} \\\\\\ \cfrac{15}{2}\cdot \cfrac{1}{1}=\cfrac{70}{x}\implies \cfrac{15}{2}=\cfrac{70}{x}\implies x=\cfrac{2\cdot 70}{15}`