Which of the following errors would be detected by the preparation of a trial balance? 

1. Goods were sold to a customer for $540. The invoice showed $5.40, which was the amount duly paid by the customer. 

2. To record the purchase of a computer on credit, both the computer account and the accounts payable account were credited. 

3. When an account from the service station was paid, the motor vehicle expenses account was debited with $149 and the cash account was credited with $194. 

4. A photographic machine was repaired, but the invoice for the work was lost in the post. 

5. Cash sales of $1470 were made. The bookkeeper correctly debited the cash account, but the corresponding credit was never made. 

6. A salesman left the keys in one of the firm’s vehicles, which was stolen and never recovered. The accountant had omitted to renew the insurance policy on the vehicle. 

7. In listing the balances of the accounts, the balance of the postages account was shown as $541 instead of the correct figure of $514, and the balance of the donations account was shown as $3 instead of the correct figure of $30.