SOLUTION: If joe can wash one car in four hours and Sam can wash one in six hours, how long would it take them to wash twenty cars?
The answer I am told is 48, but I think that it is 100,
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Question 1026600: If joe can wash one car in four hours and Sam can wash one in six hours, how long would it take them to wash twenty cars?
The answer I am told is 48, but I think that it is 100, because if they each wash ten, then jor will take fourty hours and Sam will take sixty.
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Find out how long it will take them both
to was 1 car. It will take 20 times longer
to wash 20 cars
----------------------------------
Joe's rate of working:
[ 1 car washed ] / [ 4 hrs ]
Sam's rate of working:
[ 1 car washed ] / [ 6 hrs ]
--------------------------
Let = time in hrs for them to
wash 1 car working together
------------------------------
Add their rates of working to get their rate working together
Multiply both sides by
hrs to wash 1 car working together
Now multiply by for 20 cars
Working together, it will take them 48 hrs
to wash 20 cars
----------------
A good rule to remember is that, working together, it
always takes less time than the fastest of the
2 workers
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