National Truck Company is a large trucking company that operates throughout the United States. National Truck Company uses the units-of-production (UOP) method to depreciate its trucks. National Truck Company trades in trucks often to keep driver morale high and to maximize fuel economy. Consider these facts about one Mack truck in the company's fleet: When acquired in 2012, the tractor-trailer rig cost $360,000 and was expected to remain in service for 10 years or 1,000,000 miles. Estimated residual value was $50,000. During 2012, the truck was driven 75,000 miles; during 2013, 85,000 miles; and during 2014, 135,000 miles. After 39,000 miles in 2015, the company traded in the Mack truck for a less-expensive Freightliner with a sticker price of $210,000. National Truck Company paid cash of $20,000.
Determine National's gain or loss on the transaction. Prepare the journal entry to record the trade-in of the old truck on the new one.