I need help on these 2 and the work used please

14. A sales invoice included the following information: merchandise price, $69,100; transportation, $2.100: terms 1/10. n/30, FOB shipping. Assuming that merchandise that cost $3,900 is returned before it has been paid for, that the transportation is prepaid by the seller, and that the invoice is paid within the discount period, what is the amount of cash that buyer pays the seller? 15 A company has 19 units in inventory at the beginning of May and paid $55 for each unit. On May 2, the company buys 24 more units and pays $57 for each unit. On May 5, the company sells 30 units for $84 each. If the company maintains its inventory using LIFO, what is the cost of merchandise sold