[tex]\bf \begin{array}{ccll}
\stackrel{drain}{minutes}&\stackrel{bathtub}{gallons}\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
7\frac{1}{2}&70\\
1&x
\end{array}\implies \cfrac{7\frac{1}{2}}{1}=\cfrac{70}{x}\implies \cfrac{\frac{15}{2}}{\frac{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}[/tex]
