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 same house together?

Algebra ->  Equations -> 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 same house together?      Log On


   

Question 503830: 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 same house together?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
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 same house together?
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Sally time = 4 hrs/job ; rate = 1/4 job/hr
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John time = 6 hrs/job ; rate = 1/6 job/hr
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Together time = x hrs/job ; rate = 1/x job/hr
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Equation:
rate + rate = together rate
1/4 + 1/6 = 1/x
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Multiply thru by 12x to get:
3x + 2x = 12
5x = 12
x = 12/5 = 2hr 24min (time to do the job together)
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Cheers,
Stan H.
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