SOLUTION: Max can finish repairing a machine in 4 hours. His helper can do the same job in 8 hours. Max began the job alone and work for 2 hours.His helper joined until the job was completed

Question 1013760: Max can finish repairing a machine in 4 hours. His helper can do the same job in 8 hours. Max began the job alone and work for 2 hours.His helper joined until the job was completed. How long did it take them to finish the job?
Found 2 solutions by josgarithmetic, josmiceli:
Answer by josgarithmetic(39626) (Show Source): You can put this solution on YOUR website!
Two expressions to be summed.
-----total of 1 job, Max for 2 hour and then he and helper for t hours.

Multiply both sides by 8, and then simplify,

1 hour 40 minutes
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
What fraction of the job did Max
get done in 2 hrs?
-------------------
Max's rate of working:
[ 1 machine repaired ] / [ 4 hrs ] =
Fraction of job done in 2 hrs:

-------------------
There is of the job left to do
-------------------
Let = time in hrs for them to finish job working together
Add their rates of working to get their rate working together

Multiply both sides by

hrs
It took them 4/3 hrs = 1 hr and 20 min to finish
the job working together
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