got stuck, any help?

Perpetual inventory using HAO Beginning inventory, purchases, and sales data for DVD players are as follows: The business maintains a perpetual inventory system, costing by the first-in, first-out method. a. Determine the cost of goods sold for each sale and the inventery balance after each sale, preventing the data in the form ilistrated in Exhibat 3 . Under FifO, if units are in inventory at two different costs, enter the units with the LOWER unit cost first in the Cost af Goods 5old Unit cost column and in the inventory Unit Cost coliamin. The business maintains a parpetial invertory system, costieg by the frst-in, first-aut method. are is inventory at two different costs, enter the unes whth the LOWER unt cast first in the Cost of Goods Sold Uni Cost column and in the Irivereary Unit Coat column