SOLUTION: joe and jenifer are going to wash windows. working alone, it would take jenifer 4 hours to was the windows. it would take joe 3 hours to wash the windows by himself. how long will

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Question 72968: joe and jenifer are going to wash windows. working alone, it would take jenifer 4 hours to was the windows. it would take joe 3 hours to wash the windows by himself. how long will it take then to wash the windows working together?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
joe and jenifer are going to wash windows. working alone, it would take jenifer 4 hours to was the windows. it would take joe 3 hours to wash the windows by himself. how long will it take then to wash the windows working together?
:
Let t = time required to complete the job working together
:
Let the completed job = 1
:
A simple equation:
t%2F4+%2B+t%2F3 = 1
:
Get rid of the denominators, mult eq by 12 and you have:
3t + 4t = 12
7t = 12
t = 12/7 which is 1.714 hrs or 1 hr, 43 min (.714*60)
:
Check:
1.714/4 + 1.714/3 =
.4285 + .5713 = .9998 ~ 1