SOLUTION: a man can paint a room by himself in 8 hours it takes his son 12 hours to do the same job.the man works by him self for 3 hours then his son joins him and together the two complete

Question 721179: a man can paint a room by himself in 8 hours it takes his son 12 hours to do the same job.the man works by him self for 3 hours then his son joins him and together the two complete the job..how long does the son works?
Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
a man can paint a room by himself in 8 hours it takes his son 12 hours to do the same job.the man works by him self for 3 hours then his son joins him and together the two complete the job..how long does the son works?
.
Let x = time (hrs) son worked on job
then
3(1/8) + x(1/8 + 1/12) = 1
multiplying both sides by 24:
3(3) + x(3 + 2) = 24
9 + x(5) = 24
x(5) = 15
x = 3 hours

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