i need explanation account 202

ABC Company purchased machinery on January 1,2019 at a fotal cost of $38,000. On Fobruary 3,2021 , the machinery was traded-in for a now machinery. The list price of the now machinery was $33,900. At the time of the trade in, accumulated credited for $38,000, and Loss on Dis, 900 , Accumulated Depreciation of old machinery is debited for $77,200, old Machinery is c. New Machinery in Depreciation of 38,000, and Gain on Disposal of Plant 4 sser is credited for $1,400