Question

Sue can shovel snow from her driveway in 50 minutes. Bill can do the same job in 40 minutes. How long would it take Sue and Bill to shovel the driveway if they worked together?

Answer 1

It would be:

50 * 40 / (50 + 40) = 2,000 / 90 = 22.222222 minutes

Explanation:

Answer 2

22 min 13 sec

Explanation:

Calculate the following:

1 clearance 1

---------------------------------------- = --------------------------------- = 22 min 13 sec

1 clearance 1 clearance 1/(50 min)+ 1/(40 min)

------------------ + ------------------

50 min 40 min

Note: The LCD here is 200 min.

Also note: 1 / [ 1 / 40 min ] has units "min."