SOLUTION: Amy can clean the house in 9 hours. When she works together with Tom, the job takes 5 hours. How long would it take Tom, working by himself, to clean the house?

Question 709181: Amy can clean the house in 9 hours. When she works together with Tom, the job takes 5 hours. How long would it take Tom, working by himself, to clean the house?
Found 2 solutions by josgarithmetic, josmiceli:
Answer by josgarithmetic(39620) (Show Source): You can put this solution on YOUR website!
Same job, each worker different rates.
Amys' rate
Toms' rate (Our unknown variable to find)
Sum of their rates working together

From given,

, as jobs per hour.

If you want as how many HOURS per JOB, then use reciprocal.
, hours per job.
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Add their rates of working to get rate
working together
Amy's rate is ( 1 house ) / ( 9 hrs )
Let = Tom's rate
Their rate working together is
-------------------------------------------
given:

Multiply both sides by

It will take Tom 13 hrs and 45 min working alone
check:

You can check with calculator

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