C2 through C22 represent the work days in August. In each cell total "Talk
Time" minutes are entered manually. C23 adds these up and returns them as
hours and minutes. C25 adds all the days worked (by counting the cells in C2
through C22 that have data in them). C24 is the "Average Talk Time"
(calculated by dividing C23 by C25).

What I need is a cell that will tell me the next day's "Talk Time" would
have to be to make sure that the "Average Talk Time" in C24 maintains 3 or
more hours.

Thank you!