SOLUTION: It takes you 15 minutes to wash a car and it takes a friend 6 minutes to wash a car. How long does it take the two of you to wash 7 cars if you work together?

Question 340038: It takes you 15 minutes to wash a car and it takes a friend 6 minutes to wash a car. How long does it take the two of you to wash 7 cars if you work together?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
It will take the both of you working together
7 times as long as it takes the both of you
together to wash 1 car
In words:
(your rate) + (friend's rate) = (rate working together)
Let = minutes it takes with both working

Multiply both sides by

This is the time it takes both working together to wash 1 car
For 7 cars, multiply by

It will take 30 min
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