I can't figure out how to get the answer of FIFO and LIFO and cost of good on hand, can you help me understand.

Catlet Co. uses a periodic inventory system. Its records show the following for the month of May in which 65 units were sold.

Date Explanation Units Unit Cost Total Cost
May 1 Inventory 30 $ 8 $240
May 15 Purchases 25 11 275
May 24 Purchases 35
12 420

Totals 90
$935



Compute the ending inventory at May 31 and cost of goods sold using the FIFO and LIFO methods.