I need help figuring out how to calculate the invoice amount on returned merchandise (part B).

Purchase-Related Transactions

The debits and credits from four related transactions, (1) through (4), are presented in the following T accounts. Assume that the freight terms were FOB shipping point and that the credit terms were 1/10, n/30.

Cash					Accounts Payable
		(2)	150		(3)	1,980	(1)	13,860
		(4)	11,880		(4)	11,880
Inventory
(1)	13,860	(3)	1,980
(2)	150

a. Describe each transaction.

1. Purchased merchandise on account net of discount.

2. Paid freight.

3. An allowance for return of merchandise was granted by the creditor.

4. Paid the balance due within the discount period.

b. Determine the invoice amount of the merchandise that was returned in (3).