Question 894749
It takes Jack 15 hours longer to drain a basement than Jill. If they work together, it takes 4 hours to drain a basement. How long does it take for each person to working alone?
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Draining the basement is the job.
Jill does it in some number, J, of hours, so she does 1/J per hour.
Jack does it in J+15 hours, so he does 1/(J+15) per hour.
Together, they do 1/J + 1/(J+15) per hour, and it takes them 4 hours.
Together, the do 1/4 of the job.
---> 1/J + 1/(J+15) = 1/4
Can you solve for J ?