Question

A copy machine makes 32 copies per minutes. How long does it take to make 120 copies (with minutes and seconds)

Answer 1

`\begin{array}{ccll} copies&minutes\\ \cline{1-2} 32 & 1\\ 120& x \end{array} \implies \cfrac{32}{120}~~=~~\cfrac{1}{x} \\\\\\ \cfrac{ 4 }{ 15 } ~~=~~ \cfrac{ 1 }{ x }\implies 4x=15\implies x=\cfrac{15}{4}\implies \stackrel{\textit{3 minutes and 45 seconds}}{x=3(3)/(4)}`

Answer 2

Answer: 3 min 45 sec

Explanation: