How to prepare journal entries for the following:

13-Mar Maintained delivery vehicles. Oil changes and general service work by Sallys Service Garage was completed, $200 on account.

20-Apr Sold delivery vehicle for $8,000 cash. The original vehicle was purchased for $42,000 and had accumulated depreciation of $38,000.

10-May Added a new transmission to a delivery van. The transmission was purchased and installed for $1000 on account, by Sallys Service Garage. It is estimated the transmission will extend the expected life by two years.

20-Aug Discarded office furniture with a $250 book value. The furniture was originally purchased for $900.

5-Sept New equipment was purchased on account for the office. The equipment cost $3500, and the installation, wiring, and set-up cost $1,000. There was cosmetic damage to the equipment in shipping and cost to repair it was $200. Record the transactions.

31-Dec Record the annual depreciation expense on the used delivery van from part one. #1 van.

31-Dec Record one year's amortization on the patent.