Bob Ltd. purchased two new machines for cash on 1 January 2020. Machine X cost $8,000 and Machine Y cost $20,000. Each machine was expected to have a useful life of 10 years, and residual values were estimated at $400 for Machine X and $1,000 for Machine Y. On 30 June 2021, Bob Ltd. adopted the revaluation model to account for the class of machinery. The fair values of Machine X and Machine Y were determined to be $6,400 and $9,000 respectively on that date. The useful life and residual value of Machine X was reassessed to 8 years and $300. The useful life and residual value of Machine Y was reassessed to 8 years and $800. On 2 January 2022, extensive repairs were carried out on Machine Y for $12,000 cash. Bob Ltd. expected these repairs to extend Machine Y's useful life by 4 years, and it revised Machine Y's estimated residual value to $950. Bob Ltd. decided to replace Machine X. It traded in Machine X on 31 March 2022 for new Machine C, which cost $7,500. A $3,800 trade-in was allowed for Machine X, and the balance of Machine C's cost was paid in cash. Transport and installation costs of $100 were incurred in respect to Machine C. Machine C was expected to have a useful life of 8 years and a residual value of $800. Bob Ltd. uses the straight-line depreciation method, recording depreciation to the nearest month and the nearest dollar. The end of its reporting period is 30 June. On 30 June 2022, fair values were determined to be $15,000 and $7,500 for Machines Y and C respectively. Required: Prepare general journal entries to record the above transactions and the depreciation journal entries required at January 2020, 30 June 2020, 30 June 2021, January 2022 and 31 March 2022. Please show all the required calculations as note at the end of your answer.