SOLUTION: Joe can do a certain job in 21 minutes. Bob can do the same job in 28 minutes. How long will it take them to complete the job if they work together?
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Question 640439: Joe can do a certain job in 21 minutes. Bob can do the same job in 28 minutes. How long will it take them to complete the job if they work together?
If A can do a job in x time periods, then A can do of the job in 1 time period. Likewise, if B can do the same job in y time periods, then B can do of the job in 1 time period.
So, working together, they can do
of the job in 1 time period.
Therefore, they can do the whole job in:
time periods.
John
My calculator said it, I believe it, that settles it
