SOLUTION: Bob and Alice can finish a job together in 3 hours. If Bob can do the job by himself in 5 hours, what percent of the job does Alice do?

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Question 749966: Bob and Alice can finish a job together in 3 hours. If Bob can do the job by himself in 5 hours, what percent of the job does Alice do?
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
This describes three rates and two of them are related.

Bob's rate-----------------1%2F5 jobs per hour
Alice's rate-----------------r, we do not know but wish to find
Bob and Alice Together, rate--------1%2F3 jobs per hour

The rates are shown as "jobs per hour" because in this way, two people working together makes their rates additive.
This is what that means:
Bob's rate + Alice's rate = The combined rate of Bob and Alice
1%2F5%2Br=1%2F3
Solve for r. Reminder, r will be in units of jobs per hour.