Answer:
The expression for the average cost per pair of shoes is;
12000/(1000+x) + 19 = 12000/x + 19 - 0.43
Cost per pair of shoe is $21.067
Explanation:
Here we have cost of x pair of shoes = 12000 + 19x
Therefore the average cost = 12000/x + 19
When x + 1000 is produced we have
x + 1000 = 12000 + 19(1000+x)
Therefore average cost = 12000/(1000+x) + 19
Therefore 12000/(1000+x) + 19 = 12000/x + 19 - 0.43
Therefore x = 4806.315 and we have
5806.3 = cost $ 122320
Which gives the cost per pair = $21.067.