SOLUTION: DON CLEAN THE HOUSE IN 3 HOURS. LISA CLEANED IT IN 8 HOURS. HOW LONG WILL IT TAKE THEM TO CLEAN THE HOUSE TOGETHER?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: DON CLEAN THE HOUSE IN 3 HOURS. LISA CLEANED IT IN 8 HOURS. HOW LONG WILL IT TAKE THEM TO CLEAN THE HOUSE TOGETHER?      Log On


   

Question 275932: DON CLEAN THE HOUSE IN 3 HOURS. LISA CLEANED IT IN 8 HOURS. HOW LONG WILL IT TAKE THEM TO CLEAN THE HOUSE TOGETHER?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
DON CLEAN THE HOUSE IN 3 HOURS. LISA CLEANED IT IN 8 HOURS.
HOW LONG WILL IT TAKE THEM TO CLEAN THE HOUSE TOGETHER?
:
Let t = time required working together
:
Let the completed job = 1 (a clean house)
:
Each will do a fraction of the job, the two fractions add up to 1
t%2F3 + t%2F8 = 1
Multiply the equation by 24 to clear the denominators, results
8t + 3t = 24(1)
11t = 24
t = 24%2F11%7D%7D%0D%0At+=+2%7B%7B%7B2%2F11 hrs
or
2 hrs + (2%2F11*60) ~ 11 min