[tex] \bf a)
\\\\\\
\begin{array}{ccll}
miles&minutes\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
11&74\\
1&x
\end{array}\implies \cfrac{11}{1}=\cfrac{74}{x}\implies x=\cfrac{1\cdot 74}{11}
\\\\\\
b)
\\\\\\
\begin{array}{ccll}
lbs&\$\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
20&8\\
1&x
\end{array}\implies \cfrac{20}{1}=\cfrac{8}{x}\implies x=\cfrac{1\cdot 8}{20} [/tex]
