SOLUTION: 3 painters took 15 hours to paint a house. How long would it take for 9painters to do the same

Question 755002: 3 painters took 15 hours to paint a house. How long would it take for 9painters to do the same
Found 2 solutions by josgarithmetic, DrBeeee:
Answer by josgarithmetic(39620) (Show Source): You can put this solution on YOUR website!
From this part, "3 painters took 15 hours to paint a house.", determine how long it took 1 painter to paint the house, assuming each painter uses the same rate. One painter needs three times longer than all three working together. What is 3 times 15?
45 hours for 1 painter to paint the house.

Now you want the time for 9 painters? Their rates are simply added.
Answer by DrBeeee(684) (Show Source): You can put this solution on YOUR website!
Solving this problem can be done by calculating "man-hours" to do the job, namely, paint a house.
Let MH = number of man-hours to paint a house. From the problem statment,"takes 3 painters (or "men"), 15 hours to paint a house, we get
(1) MH = 3*15 or
(2) MH = 45 painter-hours.
Now we want to know how long it will take 9 painters to do the same painting job. The answer is given by
(3) Number of hours = (Number of painter-hours required)/(number of painters) or
(4) Number of hours = MH/9 or
(5) Number of hours = 45/9 or
(6) Number of hours = 5
Answer: It will take 9 painters five hours to paint a house that takes 15 hours for 3 painters to paint.
Comment: The reason that this problem can be solved by simply using manhours is that we have the equivalent of 3 equal groups of 3 painters each. Beware other such problems require more analysis. Look in the archieve of problems of this type to learn more.
RELATED QUESTIONS
It took 4 painters 12 days to paint a house. How long would it take 3 painters to paint... (answered by josmiceli)
It takes 4 hours for 5 painters to paint a house. How long would it take for 9 painters... (answered by josgarithmetic)
Two houses painters can paint 3 houses in 4 hours. How long would it take 5 house... (answered by richwmiller)
Two houses painters can paint 3 houses in 40 hours. How long would it take 5 house... (answered by josmiceli)
Please help with the following. I have tried setting up an equation but i cannot seem to... (answered by Cromlix)
Juan can paint a house in 50 hours. Joel, who owns the new Whistler 1000, can paint the... (answered by Boreal)
It takes 3 painters 10 days to paint a house. How long does it take five painters to do... (answered by Edwin McCravy)
If three painters can paint a house in 12 hours how long would it take 4 painters to... (answered by stanbon)
IF IT TAKE 3 PAINTERS 4 HOURS TO PAINT A ROOM HOW LONG WOULD IT TAKE 1 PAINTER TO PAINT... (answered by Edwin McCravy)