Answer:
Step-by-step explanation:
C(x) = x^3 + 33x + 432
average cost, Ca = C(x)/x
Ca = x^2 + 33 + 432/x
To find the minimum, we look at the critical numbers
differentiation C(x) = 2x - 432/x^2 = 0
multiplying by x^2
2x^3 - 432 = 0
x =6
x lies in the interval [1, 10}