Question

Suppose John's car can travel 80 miles on 5 gallons of gas. How many miles can John's car travel on 15 gallons?

Answer 1

`\bf \begin{array}{ccll} miles&gallons\\ \text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\ 80&5\\ m&15 \end{array}\implies \cfrac{80}{m}=\cfrac{5}{15}\implies \cfrac{80\cdot 15}{5}=m`