<PRE><B>Question 255442</B>
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
:
{{{3/12}}} + {{{((t+3))/10}}} = 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 = {{{27/6}}}
t = 4.5 hrs to complete the job
:
:
Check solution (R works 7.5 hr)
3/12 + 7.5/10 = 
.25 + .75 = 1</PRE>