SOLUTION: Mark can paint the fence in 15 minutes and Manny can paint the fence in 30 minutes. If Manny and Mark work together how long will it take to paint the fence?

Question 281481: Mark can paint the fence in 15 minutes and Manny can paint the fence in 30 minutes. If Manny and Mark work together how long will it take to paint the fence?
Found 2 solutions by richwmiller, stanbon:
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
x/15+x/30=1
2x+x=30
x=10
They can do it together in 10 minutes
10/15+10/30=1
2/3+1/3=1
mark will do 2/3 of the job and manny 1/3

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
Mark can paint the fence in 15 minutes and Manny can paint the fence in 30 minutes. If Manny and Mark work together how long will it take to paint the fence?
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Mark rate = 1/15 job/min
Manny rate = 1/30 job/min
Together rate = 1/x job/min
--------------------------------
Equation:
rate + rate = together rate
1/15 + 1/30 = 1/x
---
Multiply thru by 30x to get:
2x + x = 30
3x = 30
x = 10 minutes (time to do the job together)
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Cheers,
Stan H.
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