help solve and explain Q1 please

Freight Terms Determine the amount to be paid in full settlement of each of two involcas, (a) and (b), assuming that credit for returns and willowances was received prior to payment and that all invoices were paid within the discount period. If required, round the answers to the nearest dollar Returns and Allowances (Invoice Amount) Merchandise (Invoice Amount) $5,150 Freight Paid by Seller $500 Freight Terms FOB destination, 2/10, 1/30 FOB shipping point, 1/10, 1/30 $1,550 b. 1,200 4.700 700 a. b. $