A chemical firm is considering purchasing pumps for its processes. It desires an ROI of 20%. The steel units are less expensive but require more frequent maintenance due to the corrosive liquids being pumped. life of all systems is five years The following costs apply. The pumps run continuously except when they are down for repairs. a. Determine the is cost points for all the alternatives. b. Plot the costs on a graph using manual or spreadsheet methods. c. Indicate the ranges of economical use for the pumps