SOLUTION: Working alone, Alex can build a fence in 8 hours, and Danny can build the same fence in 16 hours. If after working alone for 2 hours, Alex is joined by Danny, how many more hours

Question 600593: Working alone, Alex can build a fence in 8 hours, and Danny can build the same fence in 16 hours. If after working alone for 2 hours, Alex is joined by Danny, how many more hours will it take the two of them to complete the fence?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
What part of the job does Alex get done in
2 hours?
Alex's rate of working is ( 1 fence ) / ( 8 hrs )
The fraction of the job done is
There is 3/4 of the job left to do
----------
Add their rates of working to get their rate working together
( where t is in hrs )
Multiply both sides by

Multiply both sides by

It will take both of them 4 hrs to complete the fence
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