The following information pertains to Seven Dwarf Mining Equipment Limited for 2019 and 2020: Fourth quarter of 2019 First quarter of 2020 Second quarter of 2020 Third quarter of 2020 Fourth quarter of 2020 Cost of Operating the Purchasing Department $130,000 80,000 110,000 115,000 140,000 Number of Purchase Orders Issued 2,500 1,000 1,500 2,000 3,000 Required: Using the high-low method, determine the following: a. The variable cost per purchase order. b. The fixed cost of operating the purchasing department for one quarter. C. The estimated cost of operating the purchasing department in first quarter of 2021 assuming that 2,800 purchase orders will be issued