On April $01,2017,$ Sara Company purchased an equipment for $$72,000.$ Residual value at the end of an estimated five$-$ year service life expected to be $$6,000.$ The company expects the equipment to operate for $20,000$ hours. Calculate depreciation expense for $2017$ using the following depreciation method. $(2$ marks$)$

Straight line method. $(1$ marks$)$

Sum of the years' digits. $(1$ marks$)$