SOLUTION: It takes my brother 15 min to clean one window. It takes me 20 minutes to clean one window. How long will it take us to clean 12 windows.
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-> SOLUTION: It takes my brother 15 min to clean one window. It takes me 20 minutes to clean one window. How long will it take us to clean 12 windows.
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Question 339157: It takes my brother 15 min to clean one window. It takes me 20 minutes to clean one window. How long will it take us to clean 12 windows. Answer by nerdybill(7384) (Show Source):
You can put this solution on YOUR website! It takes my brother 15 min to clean one window. It takes me 20 minutes to clean one window. How long will it take us to clean 12 windows.
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Let x = minutes to clean 12 windows together
the
x(1/15 + 1/20) = 12
multiplying both sides by 300:
x(20 + 15) = 3600
35x = 3600
x = 3600/35
x = 102.86 minutes
