SOLUTION: If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together? Please help work out

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Question 745421: If Sally can paint a house in 4 hours, and John can paint the same house in 6 hour, how long will it take for both of them to paint the house together?


Please help work out the steps. I'm at 5/12x=1, but I don't know where to go next. Thank you
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Think of each person's rate as the number of jobs per hour. When they work together, the rates are added arithmetically.
Sally: 1 job per 4 hours, meaning 1%2F4 jobs per hour.
John: 1 job per 6 hours, meaning 1%2F6 jobs per hour.

Sally and John both working at the same time: %281%2F4%2B1%2F6%29 jobs per hour. Compute that expression!
The question was, how long for both of them to do the job together. This is, HOW MUCH TIME to do 1 job? That is the reciprocal of %281%2F4%2B1%2F6%29.



answer: 2 hours and 24 minutes to paint the house, when both work together