SOLUTION: A new crew of painters takes two times as long to paint a small apartment as an experienced crew. Together, both crews can paint the apartment in 6 hours. How many hours does it ta

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Question 1187966: A new crew of painters takes two times as long to paint a small apartment as an experienced crew. Together, both crews can paint the apartment in 6 hours. How many hours does it take the experienced crew to paint the apartment?
Found 2 solutions by Solver92311, greenestamps:
Answer by Solver92311(821) About Me  (Show Source):
You can put this solution on YOUR website!

Let represent the number of hours it takes the experienced crew to do the entire job by themselves. Then must represent the number of hours the inexperienced crew takes to do the entire job by themselves.

Since the experienced crew can do the entire job in hours, they can do of the job in one hour. Likewise, the inexperienced crew can do of the job in one hour.

Then, working together, they can do of the job in one hour.



Since the two crews working together can do of the job in one hour, they can do the whole job in hours. But we know that they take 6 hours working together, so:



Solve for

John

My calculator said it, I believe it, that settles it

From
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Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


You should understand, and know how to use, the formal algebraic method for solving the problem shown by the other tutor.

But you can get valuable mental exercise by solving the problem informally using logical reasoning and simple arithmetic.

The new crew works half as fast as the experienced crew, so when the two crews work together the experienced crew does 2/3 of the work.

The two crews together can do the job in 6 hours, so in 6 hours the experienced crew does 2/3 of the job.

So the number of hours it takes the experienced crew alone to do the job is (6)*(3/2) = 9 hours.

ANSWER: 9 hours