SOLUTION: It takes 5 hours for Anthony to fix a drain pipe. If his assistant helps him, it takes 3 hours. How many hours will it take for the assistant to do the job alone?

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Question 978598: It takes 5 hours for Anthony to fix a drain pipe. If his assistant helps him, it takes 3 hours. How many hours will it take for the assistant to do the job alone?
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
It takes 5 hours for Anthony to fix a drain pipe.
So Anthony's drain pipe fixing rate is 1 drain pipe fixed per 5 hours =

matrix%281%2C4%2C1%2C+drain%2C+pipe%2C+fixed%29%2Fmatrix%281%2C2%2C5%2Chr%29%22%22=%22%22matrix%281%2C2%2C1%2F5%2Cmatrix%281%2C3%2C+drain%2C+pipe%2C+fixed%29%2F%28hr%29%29%29

How many hours will it take for the assistant to do the job alone?
Let the answer be x hours.  Then the assistant's drain pipe fixing rate is
1 drain pipe fixed per x hours =

matrix%281%2C4%2C1%2C+drain%2C+pipe%2C+fixed%29%2Fmatrix%281%2C2%2Cx%2Chr%29%22%22=%22%22matrix%281%2C2%2C1%2Fx%2Cmatrix%281%2C3%2C+drain%2C+pipe%2C+fixed%29%2F%28hr%29%29%29

If his assistant helps him, it takes 3 hours.
Then their combined drain pipe fixing rate is 1 drain pipe fixed per 3 hours =

matrix%281%2C4%2C1%2C+drain%2C+pipe%2C+fixed%29%2Fmatrix%281%2C2%2C3%2Chr%29%22%22=%22%22matrix%281%2C2%2C1%2F3%2Cmatrix%281%2C3%2C+drain%2C+pipe%2C+fixed%29%2F%28hr%29%29%29 
 
The equation comes from 

%28matrix%284%2C1%2C%0D%0A%0D%0A%22Anthony%27s%22%2Cdrain_pipe%2Cfixing%2Crate%29%29%22%22%2B%22%22%28matrix%285%2C1%2C%0D%0A%0D%0Ahis%2C%22assistant%27s%22%2Cdrain_pipe%2Cfixing%2Crate%29%29%22%22=%22%22%28matrix%285%2C1%2C%0D%0A%0D%0Atheir%2Ccombined%2Cdrain_pipe%2Cfixing%2Crate%29%29

       1%2F5%22%22%2B%22%221%2Fx%22%22=%22%221%2F3

Multiply through by the LCD of 15x and solve for x.

Edwin