Please help to explain the process in getting gthe answer to this question.

A company had the following purchases and sales during its first year of operations: January: February : May: September : November : 10 20 15 12 purchases units at $155 units at $160 units at $165 units at $170 units at $175 Sales 7 units 5 units 9 units 8 units 11 units On December 31, there were 27 units remaining in ending inventory. Using the Perpetual LIFO inventoty valuation method, what is the cost of the ending inventory? (Assume all sales were made on the last day of the month.)