XYZ Corporation produced 100 units of product X and 400 units of product Y simultaneously from the same manufacturing process in the year 2019. Management considers product Y as a by-product of product X. Product Y requires further cost, including selling expense, of $0.40 per unit before it is sold.

During the period, 50 units of X and 100 units of Y were sold for $100 and $2 per unit, respectively. Total joint costs incurred during the year 2019 amounted to $8,000.

Find sales, COGS and GrossProfit Margin, and Ending inventory. Use production method and sales method to solve.