Zephyr Minerals completed the following transactions involving machinery. Machine No. 1550 was purchased for cash on April 1, 2017, at an installed cost of $54,000. Its useful life was estimated to be six years with a $3,000 trade-in value. Straight-line depreciation was recorded for t and 2019. On March 29, 2020, it was traded for Machine No. 1795, with an installed cash price of $63,000. A trade-in allowance of $30,310 was received for Machine No. 1550, and the balance was paid in cash. and Machine No. 1795 could not be determined. Machine No. 1795's life was predicted to be four years with a trade-in value of $8,300. Double declining-balance depreciation on this machine was recorded each December 31. On October 2, 2021, it was trad an installed cash price of $481,000, the machine's fair value. A trade-in allowance of $10,000 was received for Machine No. 1795, and the balance was paid in cash. It was estimated that Machine No. BT-311 would produce 200,000 units of product during its five year useful life, after which it would have a $15,000 trade-in value. Units-of-production depreciation was recorde which it produced 25,000 units of product. Between January 1, 2022, and August 21, 2024, the machine produced 100,000 more units. On August 21, 2024, it was sold for $81,300. Required: Prepare journal entries to record: (Round intermediate calculations to the nearest whole dollar.) a. The depreciation expense recorded to the nearest whole month on the first December 31 of each machine's life. (Round the final answers to the nearest whole dollar. If no entry is required for a transacti required" in the first account field.) b. The purchase/exchange/disposal of each machine. (Round the final answers to the nearest whole dollar. If no entry is required for a transaction, select "No journal entry required" in the first account field.)