please explain thanks

Cullumber Company sells 279 units of its products for $18 each to Gary Inc. for cash. Cullumber allows Gary to return any unused product within 30 days and receive a full refund. The cost of each product is $13. To determine the transaction price, Cullumber decides that the approach that is most predictive of the amount of consideration to which it will be entitled is the probability-weighted amount. Using the probability-weighted amount, Cullumber estimates that (1) 11 products will be returned and (2) the returned products are expected to be resold at a profit. (a) Indicate the amount of net sales. Net sales \$ (b) Indicate the amount of estimated liability for refunds. Liability for refunds (c) Indicate the amount of cost of goods sold that Cullumber should report in its financial statements (assume that none of the products have been returned at the financial statement date). Cost of goods sold \$