Writing.com has a beginning inventory of 16 sets of pens at a cost of $2.12 each. During the year, Writing.com purchased 8 sets at $2.15, 9 sets at $2.25, 14 sets at $3.05, and 13 sets at $3.20. By the end of the year, 29 sets were sold. a. Calculate the number of pen sets in stock. b. Calculate the cost of ending inventory under LIFO, FIFO, and weighted-average methods. (Round your intermediate calculation and final answers to the nearest cent.)