Question 184097: A worker can cover a parking lot with asphalt in 10 hours. With the help of an assistant, the work can be done in 6 hours. How long would it take the assistant, working alone, to cover the parking lot with asphalt?
worker a 10(1/10)
worker b t(1/6)
10(1/10)=t(1/6)
I think I am setting the problem up wrong. Thank you.
Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website! A worker can cover a parking lot with asphalt in 10 hours. With the help of an assistant, the work can be done in 6 hours. How long would it take the assistant, working alone, to cover the parking lot with asphalt?
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To add the efforts, you have to get them in the same units. One person does the job in 10 hours, so he does 1/10 of the job per hour.
The other person does 1/6 of the job per hour.
Add 1/10 and 1/6
1/10 + 1/6 = 3/30 + 5/30 = 8/30 together.
So the job take 30/8 hour = 15/4 or 3.75 hours.
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A shortcut to this type of problem (with 2 only, not 3 or more) is
product/sum
6*10/(6+10) = 60/16 = 15/4 same answer.
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