Math 110 Course Resources - Definite Integrals Course Packet on the Fundamental Theorem of Calculus The marginal cost function associated with producing x widgets is given by C'(x) = -0.2x +75 where C'(x) is measured in dollars/unit and x denotes the number of widgets. Compute the total cost incurred from producing the 11th through 20th units of the day. 647.10 x dollars