SOLUTION: Melinda can weed her garden in 40 minutes. When Bob helps, it takes them 15 minutes. How long would it take Bob to weed the garden alone?

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Question 721109: Melinda can weed her garden in 40 minutes. When Bob helps, it takes them 15 minutes. How long would it take Bob to weed the garden alone?
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
Look at their rates but in the form of weed-the-garden per minute.

Melinda: 1 job per 40 minutes, or 1/40 jobs per minute.
Melinda plus Bob: 1/15 jobs per minute.

You want the rate for Bob alone? The rates are additive. Melinda plus Bob = Melinda+Bob.

highlight%281%2F40%2BB=1%2F15%29, where B is the rate at which Bob alone can weed the garden. This is all, again, jobs per minute. You are actually looking for the answer to the reciprocal of B.