SOLUTION: I tried on this problem already (not from a textbook) and I'm not sure if I'm getting it, I've got answers ranging from 18 mins to 8.89 minutes. Here's the problem:
Jack can wa
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-> SOLUTION: I tried on this problem already (not from a textbook) and I'm not sure if I'm getting it, I've got answers ranging from 18 mins to 8.89 minutes. Here's the problem:
Jack can wa
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Question 134441: I tried on this problem already (not from a textbook) and I'm not sure if I'm getting it, I've got answers ranging from 18 mins to 8.89 minutes. Here's the problem:
Jack can wash a car in 16 minutes; Jill can wash the same car in 20 minutes. How long will it take both of them working together to wash the car?
This is what I've done: (16 + 20) / 2 = 18 mins
I've also tried using the example of the solution to problem 133568 and I got 8.89 mins.
I'm not sure which is correct and I'd really appreciate the help. Thank you. Answer by checkley71(8403) (Show Source):
You can put this solution on YOUR website! YOU ARE USING THE WRONG EQUATION FOR THIS PROBLEM.
THE PROPER EQUATION IS THE PRODUCT DIVIDED BY THE SUM OF THE 2 TIMES.
16*20/(16+20)=320/36=8.889 MINUTES TO WASH THE CAR WORKING TOGETHER.
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