The following data relate to the Machinery account of Kingbird, Inc. at December 31, 2020. Original cost Year purchased Useful life Salvage value Depreciation method Accum. depr through 2020* A $55,660 2015 10 years $3,751 Sum-of-the-years'-digits $37,752 Machinery B D $61,710 $96,800 $96,800 2016 2017 2019 15,000 hours 15 years 10 years $3,630 $6,050 $6,050 Activity Straight-line Double-declining balance $42,592 $18,150 $19,360 *In the year an asset is purchased, Kingbird, Inc. does not record any depreciation expense on the asset. In the year an asset is retired or traded in, Kingbird, Inc. takes a full year's depreciation on the asset. The following transactions occurred during 2021. (a) On May 5, Machine A was sold for $15,730 cash. The company's bookkeeper recorded this retirement in the following manner in the cash receipts journal. Cash 15,730 Machinery (Machine A) 15,730 (b) On December 31, it was determined that Machine B had been used 2,000 hours during 2021. (c) On December 31, before computing depreciation expense on Machine C, the management of Kingbird, Inc. decided the useful life remaining from January 1, 2021, was 10 years. (d) On December 31, it was discovered that a machine purchased in 2020 had been expensed completely in that year. This machine cost $33,880 and has a useful life of 10 years and no salvage value. Management has decided to use the double-declining- balance method for this machine, which can be referred to as "Machine E." Debit Credit No. Account Titles and Explanation (a) Depreciation Expense 4524 Accumulated Depreciation-Machinery 4524 (To record current depreciation) Accumulated Depreciation-Machinery 40716 Machinery 38280 2436 Gain on Disposal of Machinery (To properly record the sale) (b) Depreciation Expense 8352 Accumulated Depreciation-Machinery 8352 (c) Depreciation Expense 7260 Accumulated Depreciation-Machinery 7260 (d) Machinery 33880 Retained Earnings 33880 (To correct the incorrect expensing of the asset in 2020) Depreciation Expense 6776 Accumulated Depreciation-Machinery 6776 (To record depreciation)