Donald Mac Inc. purchased a delivery truck on July 1, 2020. The cost of the truck is $90,000, the residual value is $5,000, the useful life is 4 years. The company's year end is December 31 . Prepare a depreciation schedule that shows the annual depreciation expense on the truck for its 4year life using: a) Straight line depreciation method. b) diminishing balance depreciation method if the company uses double the straight rate method