The Dewitt Company has found that the rate of change of its average cost of producing a product is

Question: The Dewitt Company has found that the rate of change of its average cost of producing a product is

\[\bar{C}'\left( x \right)=\frac{1}{5}-\frac{100}{{{x}^{2}}}\]

where x is the number of units and cost is in dollars. The average cost of producing 20 units is $40.00. Find the average cost of producing 100 units of the product.