SOLUTION: Joan can shovel a certain driveway in 50 minutes. If mary can shovel the same driveway in 20 minutes, how long will it take them, to the nearest minute, to shove the driveway if t

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Question 379651: Joan can shovel a certain driveway in 50 minutes. If mary can shovel the same driveway in 20 minutes, how long will it take them, to the nearest minute, to shove the driveway if they work together?
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
Joan can shovel a certain driveway in 50 minutes. If mary can shovel the same driveway in 20 minutes, how long will it take them, to the nearest minute, to shove the driveway if they work together?
.
Let x = time (minutes) it takes for both
then
x(1/50 + 1/20) = 1
multiplying both sides by 1000:
x(20 + 50) = 1000
x(70) = 1000
x = 14.29
rounded:
x = 14 minutes