I need help with these three calculus questions

16. V Compute the average value of f(x) = \\ 3x + 1 on the interval [0,5]. O 41/15 131/45 O 124/45 14/5 O 127/45 Viewing Saved Work Revert to Last Response 17. The marginal cost function associated with producing x widgets is given by C'(x) = -0.6x + 30 where C'(x) is measured in dollars/unit and x denotes the number of widgets. Find the total cost C(x) incurred from producing the 11th through 40th units of the day. O $490 O $450 O $500 O $400 O $430 Viewing Saved Work Revert to Last Response 18. V Find the area of the region bounded by f(x) = v x and g(x) = x/2 on the interval [0,16]. 16/3 64/3 24 0 8/3