Question 40084
Let C be the cost.  So we have
C = .07w + 13.3
Now if w = 375, we just plug it in and calculate
C = .07*375 + 13.3
C = $39.55
We divide that by 375 to find the average cost...
Average = $39.55/375 = $.1055 or a little more than 10 1/2 cents each...