Answer:
(a) 
Dr Accounts Receivable $635,000
Cr 7/10/2020 Sales Revenue $635,000
Dr Cost of Goods Sold $508,000
 Cr Inventory $508,000
 (b)
Dr Sales Returns & Allowances $82,700 
Cr 10/11/2020.Accounts Receivable $82,700
Dr Returned Inventory $66,160
Cr Cost of Goods Sold $66,160
 10/31/2020 No entries are needed as the return period has expired. 
Explanation:
 (a) 
Dr Accounts Receivable $635,000
Cr 7/10/2020 Sales Revenue $635,000
Dr Cost of Goods Sold $508,000
 Cr Inventory $508,000
 (b)
Dr Sales Returns & Allowances $82,700 
Cr 10/11/2020.Accounts Receivable $82,700
Dr Returned Inventory $66,160
Cr Cost of Goods Sold $66,160
($508,000 / $635,000) x $82,700= $66,160
 10/31/2020 No entries are needed as the return period has expired.