SOLUTION: A janitor can clean a building in about 2 hours. When he has a helper, he can do it in 1.25 hours. how long would it take the helper to do it on his own? the answer is 3.33 hours b

Question 1078978: A janitor can clean a building in about 2 hours. When he has a helper, he can do it in 1.25 hours. how long would it take the helper to do it on his own? the answer is 3.33 hours but how would you set the problem up?
Found 2 solutions by Boreal, josgarithmetic:
Answer by Boreal(15235) (Show Source): You can put this solution on YOUR website!
in an hour the janitor can clean 1/2 the building
with a helper they both can clean 1/1.25 of the building in an hour
therefore, in 1 hour
(1/2)+(1/x)=1/1.25, where x is the number of hours the helper takes
multiply everything by 1.25 to get the right side equal to 1, 1 complete building. This doesn't have to be done but then the answer is for 0.8 of the building and more work has to be done.
1.25/2+1.25/x=1
Now by 2x
1.25x+2.5=2x
0.75x=2.5
x=3.33 hours
Answer by josgarithmetic(39617) (Show Source): You can put this solution on YOUR website!
x, time for just the helper alone

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