Janet​, an experienced shipping​ clerk, can fill a certain order in 5 hours. Jim​, a new​ clerk, needs 7 hours to do the same job. Working​ together, how long will it take them to fill the​ order?

Answer 1

To solve this problem, we can use the formula for working together:

1/T = 1/A + 1/B

where T is the time it takes to do the job together, A is the time it takes for Janet to do the job alone, and B is the time it takes for Jim to do the job alone.

In this case, A = 5 hours and B = 7 hours.

Plugging in the values, we get:

1/T = 1/5 + 1/7

To solve for T, we can find the common denominator:

1/T = (7 + 5) / (5*7)

1/T = 12/35

Now we can solve for T by taking the reciprocal:

T = 35/12

Thus, it will take them approximately 2.92 hours (or 2 hours and 55 minutes) to fill the order together.