Determining amounts to be paid on invoices

Determine the amount to be paid in full settlement of each of the following invoices, assuming that credit for returns and allowances was received prior to payment and that all invoices were paid within the discount period:

Invoice	Merchandise Invoice Amount	Freight Paid by Seller	FOB	Customer Returns and Allowances
a.	$20,700		FOB destination, n/30	$1,000
b.	10,800	$400	FOB shipping point, 1/10, n/30	1,300
c.	5,900		FOB shipping point, 1/10, n/30	500
d.	3,500	100	FOB shipping point, 1/10, n/30	500
e.	2,500		FOB destination, 2/10, n/30

Invoice	Amount
a.	$fill in the blank 1
b.	$fill in the blank 2
c.	$fill in the blank 3
d.	$fill in the blank 4
e.	$fill in the blank 5