Question

Charles is going camping with his family. Their campsite is three fourths mile away. They walk at a steady speed of 1 and one fourth mile divided by hour. How many minutes will it take them to get to the? campsite?

Answer 1

Charles and his family walk at a steady speed of 1¼ mile per hour, so in hour, namely 60 minutes, they have covered 1¼ miles, how many minutes will it take them to cover 3/4 of a mile?

`\bf \begin{array}{ccll} miles&minutes\\ \cline{1-2}\\ 1(1)/(4)&60\\\\ (3)/(4)&x \end{array}\implies \cfrac{~~1(1)/(4)~~}{(3)/(4)}=\cfrac{60}{x}\implies \cfrac{~~(5)/(4)~~}{(3)/(4)}=\cfrac{60}{x}\implies \cfrac{5}{4}\cdot \cfrac{4}{3}=\cfrac{60}{x} \\\\\\ \cfrac{5}{3}=\cfrac{60}{x}\implies 5x=180\implies x=\cfrac{180}{5}\implies x=36`