Peter's company made the following merchandise purchases during the current year.

Feb 2- 25000 units @ $42 each

Apr. 8- 5000 units @ $39 each

may 30- 18500 units @ $ 40 each

Aug 2 - 9000 units @ $41 each

There was no beginning inventory. If Peter uses, first in, first out method and ending inventory consisted of 12000 units, what is the cost of the ending inventory. I don't know how to calculate this problem. Please help