Explanation:
The journal entries are as follows
1. Cash A/c Dr $30,960
To Common stock A/c $30,960
(Being the cash is invested in exchange for common stock)
2. No journal entry is required
3. Office furniture A/c Dr $3,630
To Account payable A/c $3,630
(Being the office furniture is purchased on account)
4. Account receivable A/c Dr $11,130
To Service revenue $11,130
(Being the goods are sold on credit)
5. Cash A/c Dr $230
To Service revenue A/c $230
(Being cash received is recorded)
6. Account payable A/c Dr $640
To Cash A/c $640
(Being the payment is made)
7. Salaries expense A/c Dr $3,330
To Cash A/c $3,330
(Being the salaries is paid for cash)