t the beginning of its operations in March $2020,$ Mastiff Supplies Ltd$.$ began with $7,260$ units of inventory that it purchased at a cost $$6\mathrm{.}80$ each. The company's purchases during March were as follows:March $134,840$ units @$$7,70$Sales during March:March $24,840$ unitsMarch $202,760$ unitsastiff Supplies uses a periodic inventory system.