SOLUTION: 1) Working alone, Coleen can paint a house in 2hr less than James. Working together, they can paint the house in 10hr. How long would it take James to paint the house?

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Question 127987: 1) Working alone, Coleen can paint a house in 2hr less than James. Working together, they can paint the house in 10hr. How long would it take James to paint the house?
Answer by checkley71(8403) About Me  (Show Source):
You can put this solution on YOUR website!
J(J-2)/[J+(J-2)]=10
(J^2-2J)/(2J-2)=10 NOW CROSS MULTIPLY
J^2-2J=10(2J-2)
J^2-2J=20J-20
J^2-2J-20J+20=0
J^2-22J+20
USING THE QUADRATIC EQUATION:x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+ WE GET:
J=(22+-SQRT[-22^2-4*1*20])/2*1
J=(22+-SQRT[484-80])/2
J=(22+-SQRT404)/2
J=(22+-20.1)/2
J=(22+20.1)/2
J=42.01/2
J=21.05 HOURS - TIME FOR JAMES TO PAINT THE HOUSE ALONE.
PROOF:
21.05*19.05/(21.05+19.05)=10
401/40.1=10
10=10