SOLUTION: Sally can paint a house in 4 hours and Joe can paint the same house in 6 hours. If they work together how long will it take them to paint the house? thanks

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Sally can paint a house in 4 hours and Joe can paint the same house in 6 hours. If they work together how long will it take them to paint the house? thanks      Log On


   

Question 1119: Sally can paint a house in 4 hours and Joe can paint the same house in 6 hours. If they work together how long will it take them to paint the house?
thanks
Found 3 solutions by usyim88hk, KtipsayFoozeBamps, timofer:
Answer by usyim88hk(158) About Me  (Show Source):
You can put this solution on YOUR website!
First you have to know how much painting they could done in one hour
:
For one hour, she can paint 1/4 of the house because 1 divide by 4 is 1/4
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For Joe, he can paint 1/6 of the house in one hour because 1 divide by 6 is 1/6
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So now we can add 1/4 and 1/6 together to determine how much they could paint in one hour which is equal to 3/12 + 2/12 = (5/12)
:
So they could finish 5/12 of painting in one hour, now we can devide 1 by (5/12) to determine how much time they need to paint the whole house
:
1/(5/12) = 2.4
:
So they took 2.4 hour (or 2 hours 24 mins) to paint a house together

Answer by KtipsayFoozeBamps(1) About Me  (Show Source):
Answer by timofer(104) About Me  (Show Source):
You can put this solution on YOUR website!
Sally, 1 house in 4 hours
Joe, 1 house in 6 hours

Both together, the combined rate is 1%2F4%2B1%2F6=3%2F12%2B2%2F12=5%2F12housesperhours.


In hours per 1 house, this is 12%2F5=2%262%2F5
or 2 hours 24 minutes.