SOLUTION: jack can clean the house in 12 hours, sam can do the same job in 9 hours. How long would it take if they worked together?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: jack can clean the house in 12 hours, sam can do the same job in 9 hours. How long would it take if they worked together?      Log On


   



Question 881635: jack can clean the house in 12 hours, sam can do the same job in 9 hours. How long would it take if they worked together?
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
1%2F12+%2B+1%2F9+=+1%2Fx
3x + 4x = 36
7x = 36
x = 36/7= 5 1/7 hr