Suppose that N(x) = x denotes the number of bags sold by a shop, and the selling price per bag is
given by p(x) = 320 – 8x, for 0 ≤ x ≤ 10. Suppose further that the cost of producing x bags is given
by C(x) = 200x. Find (a) (N ∙ p)(x) and (b) (N ∙ p – C)(x). What do these functions represent?