A company produces x units of output at a total cost of 1/3 x^3 – 18x^2 + 160x. Output at which average cost is equal to marginal cost is:

Answer 1

average cost is
(1/3 x^3 – 18x^2 + 160x)/x
= 1/3 x^2 - 18x + 160

marginal cost is

x^2-26x+160

so, where is

1/3 x^2 - 18x = x^2 - 26x ?

Answer 2

18x