Please help with part B

Problem 8-5A Tokyo Audio uses a periodic inventory system. One of the store's most popular products is an MP3 car stereo system. The inventory quantities, purchases, and sales of this product for the most recent year are as follows: Number Cost of Units per Unit Total Cost Inventory, 1 Jan. $2.990 29,900 First purchase (12 May) 45,900 3,060 15 Second purchase (9 July). 61,600 3,080 Third purchase (4 Oct.) 25,200 3,150 60,800 Fourth purchase (18 Dec.) 3,200 19 $223,400 Goods available for sale 72 Units sold during the year 51 Inventory, 31 Dec. Instructions a. Using periodic costing procedures, compute the cost of the 31 December inventory and the cost of goods sold for the MP3 systems during the year under each of the following cost flow assumptions: 1. First-in, first-out 2. Weighted average cost (round to nearest dollar, except unit cost). b. Which of the two inventory pricing methods provides the most realistic year-end valuation of inventory in light of the net realizable value (NRV) of the MP3 units? Does this same method also produce the most realistic measure of profit in light of the NRV of the MP3 systems when they are sold? Explain