A manufacturer has the following costs in producing x toasters in one day for 0 < x < 150: fixed costs, $320; unit production cost, $20 per toaster; equipment maintenance and repairs, x^2 /20 dollars. Thus, the cost of manufacturing x toasters in one day is given by C(x)= x^2/20 + 20x + 320 0 < < 150. and the average cost per toaster is given by /C(x)= C(x)/x= x/20 + 20 + 320/x 0