Answer: 46 times
Step-by-step explanation:
Since $110 is the constant and 6 is the coefficient because it is changing with each time he rents a tennis ball. The equation is 110+6t=386 where t in this case can represent (return groundstrokes)
110+6t=386 solve for t
6t=276
t=46
So he can return ground strokes 46 times
