The average monthly sales (S) volume (in thousands of dollars) for a company depends on the number of hours of training x of its sales according to the function:
S=40/x+10+x/4, 10 ≤ x ≤ 100.

How many hours of training needed to have an average monthly sale
$17,850?

The average monthly sales S volume in thousands of dollars for a company depends on the number of hours of training x of its sales according to the function S40 class=