On January 1, 2020, a machine was purchased for $88,000. The machine is estimated to have a salvage value of $8,000 and a useful life of 5 years. This machine can operate for 100,000 hours before finally having to be replaced. The company operates its machines with the following information:

Years	Usage
2020	30.000 hours
2021	15.000 hours
2022	25.000 hours
2023	10.000 hours
2024	20.000 hours

Assume the financial year ends on September 30. Instructions: calculate the annual depreciation expense for 2020 and 2021 using the following method: 1. Straight line method; 2. Double declining balance method; 3. The method of the sum of the years digits; and 4. Activity method