SOLUTION: If george washed a car in 20 minutes and sally washed the same car in 15 minutes how long would it take them to wash the car together?

Question 973876: If george washed a car in 20 minutes and sally washed the same car in 15 minutes how long would it take them to wash the car together?
Found 2 solutions by josmiceli, 428225:
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Add their rates of washing to get
their rate washing together
George's rate:
[ 1 car ] / [ 20 min ]
Sally's rate:
[ 1 car ] / [ 15 min ]
------------------
Let = time in minutes working together

Multiply both sides by

min
It takes them 12 min working together

Answer by 428225(90) (Show Source): You can put this solution on YOUR website!
The working out should be:

Therefore

t=8.57 minutes
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