Solution :
a). The sales revenue
Closing balance 2800
Add:cash collected from the customer 78,000
Less:opening balance (9800)
Sales revenue 71000
b). Cost of the goods sold
Cash pf payment for the purchase 58,000
Add:decrease in the inventory (6800-5800) 1000
Add:increase in the account payable (14,800-11,800) 3000
Cost of the good sold 62000
c). The insurance expenses = (4800 + 4800 - 7300) = 2300
d). the salaries and the wages expenses = 2800 + 9800 - 4800
= 7800
Journal entry
Accounts Debit Credit
Income summary account
sales revenue account
Cost of the goods sold 62000
insurance expenses 2300
Salaries & wages expenses 7800
Income summary account 72100