E$6\mathrm{.}5($LO $2),$ AP REI sells snowboards. Assume the following information relates to REI's purchases of snowboards during September. During the same month, $102$ snowboards were sold. REI uses a periodic inventory system.

$\backslash$table$[[$Date$,$Explanation,Units,Unit Cost,Total Cost$],[$Sept$.1,$Inventory,$12,$$$100,$$ $1,200],[$Sept$.12,$Purchases,$45,103,4,635],[$Sept$.19,$Purchases,$50,104,4,635],[$Sept$.26,$Purchases,$20,105,5,2002,100],[,$Totals,$127,,$$$13,135]]$

Instructions

a$.$ Compute the ending inventory at September $30$ using FIFO, LIFO, and average$-$cost$.$

b$.$ Compute the cost of goods sold for the month using the FIFO, LIFO, and average$-$cost methods. $($For average$-$cost$,$ round the average unit cost to three decimal places.$)$

Compute irventory and cost of goods sold using periodic FIFO, LIFO, and average$-$cost$.$

$($int$)$