SOLUTION: John can paint the fence around his house in 15 hours, while his brother chad can do it in 18 hours. If John paints for 7 hours alone and turns the rest over to chad, how long wil

Algebra ->  Rate-of-work-word-problems -> SOLUTION: John can paint the fence around his house in 15 hours, while his brother chad can do it in 18 hours. If John paints for 7 hours alone and turns the rest over to chad, how long wil      Log On


   



Question 746637: John can paint the fence around his house in 15 hours, while his brother chad can do it in 18 hours. If John paints for 7 hours alone and turns the rest over to chad, how long will it take chad to finish painting the fence?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
John can paint the fence around his house in 15 hours, while his brother chad can do it in 18 hours.
If John paints for 7 hours alone and turns the rest over to chad, how long will it take chad to finish painting the fence?
:
Let t = time for Chad to finish the fence
Let the completed job = 1; (a painted fence)
:
A typical shared work equation
7%2F15 + t%2F18 = 1
multiply eq by the least common multiple of 15 & 18; that's 90, results:
6(7) + 5t = 90
5t = 90 - 42
t = 48/5
t = 9.6 hrs for Chad to finish the job
:
:
Check this on a calc`: 7/15 + 9.6/18 = 1