Question

It takes 90 minutes to wash 20 vehicles at a car wash. At this rate, how many minutes does it take to wash 5 vehicles?

Answer 1

22.5 minutes

Explanation:

Make a proportion:
`text{minutes}/text{number of vehicles}`

`text{90 minutes}/text{20 vehicles } = x/text{5 vehicles}`

Cross multiply and solve for `x`
`90(5) = 20(x)`
`450 = 20x`
`22.5 = x`

Answer: 22.5 minutes