Stefan requires 6 hours to wash the cars by himself. In one hour he washes 1/6 of the cars. Misha can wash the cars by herself in 5 hours. In 1 hour she can wash 1/5 of the cars.

Stefan has 2.5 hours to wash the cars as he has to go to the football game. In 2.5 hours he has washed (1/6)*2.5 = 5/12 of the cars. This leaves 1 - 5/12 = 7/12 of the cars for Misha to wash. As she washes cars at the rate of 1/5 per hour, it would take her (7/12)/` `(1/5) = (5*7)/12 = 35/12 hours to wash the remaining cars.

35/12 hours is equal to 175 minutes or 2 hours 55 minutes.

**Misha finishes washing the cars in 35/12 hours after Stefan leaves.**

## We’ll help your grades soar

Start your 48-hour free trial and unlock all the summaries, Q&A, and analyses you need to get better grades now.

- 30,000+ book summaries
- 20% study tools discount
- Ad-free content
- PDF downloads
- 300,000+ answers
- 5-star customer support

Already a member? Log in here.

Are you a teacher? Sign up now