Steven and Sarah can finish apiece of work in 18days Steven

Steven and Sarah can finish apiece of work in 18days. Steven can do the job himself in twenty-four days. If Sarah wanted to do the job alone, how long would it take her?

Solution

First, find out how much of the job can be done in one day by Steven & Sarah.
If it takes them both 18 days to finish the job, then in one day they can do 1/18 of the job.
Now find out how much of the job Steven can do in one day. If it takes Steven 24 days to finish the job, then in one day, he can do 1/24 of the job.
So, the amount of the job Sarah can in one day can be found by subtracting the amount that Steven can do from the amount that Steven & Sarah can do.
This is: 1/18 - 1/24 Find the common denominator. It\'s 72
Write the equivalent fractions then subtract.
4/72 - 3/72 = 1/72 of the entire job. This is what Sarah can do in one day.
So it will take Sarah 72 days to complete the job.