A manufacturer estimates that when q thousand units of a particular commodity are produced each month, the total cost will be C(q) = 0.4q^2+3q+40 thousand dollars, and all q units can be sold at a price of p(q) = 22.2 - 1.2q dollars per unit.
At what level of production is the average cost per unit A(q) = C(q)/q minimized?
