Please show work so I can learn, thanks

62. Business: average revenue, cost, and profit. Given revenue and cost functions R(x) = 40x and C (x) = 5% + 100, find each of the following. Assume R(x) and C(x) are in dollars and x is the number of lamps produced. [1.6] a) The average cost, the average revenue, and the aver age profit when x lamps are produced and sold b) The rate at which average cost is changing when 9 lamps are produced