What is Perpetual System, Moving-Average Cost Flow?

Nash Company manufactures many products for use in the airline industry. Presented below is information concerning one of its products, the Orbit. Compute cost of goods sold, assuming Nash uses: (Round average cost per unit to 2 decimal places, eg. 2.76 and final answers to 0 decimal places, eg. 6,548 .) Compute cost of goods sold, assuming Nash uses: (Round average cost per unit to 2 decimal ploces, eg. 2.76 and final answers to 0 decimal places, eg. 6,548.)