Answer:
a) December 3, 202x, merchandise sold to Sheridan Co., terms 3/10, n/30
Dr Accounts receivable 513,500
Cr Sales revenue 513,500
Dr Cost of goods sold 318,300
Cr Merchandise inventory 318,300
December 8, merchandise allowance
Dr Sales returns and allowances 24,700
Cr Accounts receivable 24,700
December 13, invoice collected from Sheridan Co.
Dr Cash 474,136
Dr Sales discounts 14,664
Cr Accounts receivable 488,800
b) January 2, invoice collected from Sheridan Co.
Dr Cash 488,800
Cr Accounts receivable 488,800