SOLUTION: John can paint a house in 4 hours and Sue can paint the same house in 6 hours, how much time will it take for them to paint the house together?

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Question 324691: John can paint a house in 4 hours and Sue can paint the same house in 6 hours, how much time will it take for them to paint the house together?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
John can paint a house in 4 hours and Sue can paint the same house in 6 hours,
how much time will it take for them to paint the house together?
:
Let t = time required when working together
Let the completed job = 1 (a painted house)
:
Each will do a fraction of the job, the two fractions will add up to 1
:
t%2F4 + t%2F6 = 1
multiply by 12 to get rid of the denominators, results:
3t + 2t = 12
5t = 12
t = 12%2F5
t = 2.4 hrs working together
:
:
Check solution
2.4/4 + 2.4/6 =
.6 + .4 = 1