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If Jim Roller can paint a room in 3 hours while John Brush would take 5 hours, how long will they take if they work together?
 one year ago
 one year ago
If Jim Roller can paint a room in 3 hours while John Brush would take 5 hours, how long will they take if they work together?
 one year ago
 one year ago

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emilie.liBest ResponseYou've already chosen the best response.0
i found this: http://answers.yahoo.com/question/index?qid=20070729140155AAUsPDt
 one year ago

gaby236Best ResponseYou've already chosen the best response.0
a;1/8 hour b;8/15 hour c; 7/8 hours
 one year ago

wioBest ResponseYou've already chosen the best response.0
I know, but what level of math?
 one year ago

wioBest ResponseYou've already chosen the best response.0
You need to make a system of equations.
 one year ago

wioBest ResponseYou've already chosen the best response.0
Let, \(t\) be the time it takes to paint the room. \(r\) is the rate that Roller to paints it, \(b\) is the rate that Brush paints it.
 one year ago

wioBest ResponseYou've already chosen the best response.0
We know that \[ 3r = 5b \]
 one year ago

wioBest ResponseYou've already chosen the best response.0
We also know that \[ (r+b)t = 3r = 5b \]
 one year ago

wioBest ResponseYou've already chosen the best response.0
First solve for \(r\) in terms of \(b\) \[ 3r=5b\implies r = \frac{5}{3}b \]Now plug it into equation 2 \[ \left(\frac{5}{3}b+b\right)t=5b \]
 one year ago

RadEnBest ResponseYou've already chosen the best response.0
shorcut way : 3*5/(3+5) = 15/8 long way :p v1+v2 = x/3 + x/5 = 8x/15 = x/(15/8) so, if they work together will take 15/8 hours
 one year ago

RadEnBest ResponseYou've already chosen the best response.0
no correct options there
 one year ago
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