SOLUTION: Phil can paint the garage in 12 hrs., and Rick can do it in 10 hrs. They work together for 3 hrs. How long will it take Rick to finish the job alone?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Phil can paint the garage in 12 hrs., and Rick can do it in 10 hrs. They work together for 3 hrs. How long will it take Rick to finish the job alone?      Log On


   

Question 255442: Phil can paint the garage in 12 hrs., and Rick can do it in 10 hrs. They work together for 3 hrs. How long will it take Rick to finish the job alone?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Phil can paint the garage in 12 hrs., and Rick can do it in 10 hrs.
They work together for 3 hrs.
How long will it take Rick to finish the job alone?
:
Let t = time for required by Rick to finish the job
:
Let completed job = 1
:
3%2F12 + %28%28t%2B3%29%29%2F10 = 1
Get rid of the denominators, multiply by 60, results:
5(3) + 6(t+3) = 60
:
15 + 6t + 18 = 60
:
6t = 60 - 15 - 18
:
6t = 27
t = 27%2F6
t = 4.5 hrs to complete the job
:
:
Check solution (R works 7.5 hr)
3/12 + 7.5/10 =
.25 + .75 = 1