SOLUTION: If sally can paint a house in 4 hours and john can paint the same house in 6 hours how long will it take for both of them to paint the house together?

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Question 198212: If sally can paint a house in 4 hours and john can paint the same house in 6 hours how long will it take for both of them to paint the house together?
Found 2 solutions by solver91311, josmiceli:
Answer by solver91311(24713) (Show Source):
You can put this solution on YOUR website!

If A can do a job in x time periods, then A can do of the job in 1 time period. Likewise, if B can do the same job in y time periods, then B can do of the job in 1 time period.

So, working together, they can do

of the job in 1 time period.

Therefore, they can do the whole job in:

time periods.

John

Answer by josmiceli(19441) (Show Source):
You can put this solution on YOUR website!
In words:
sally's rate of painting is (1 house) / (4 hours)
John's rate of painting is (1 house) / (6 hours)
If I add the rates, I get the rate of both
working together

Multiply both sides by

Working together, they can paint the house in 2.4 hours