On $1$st January $2021,$ Fred Limited purchased an equipment costing GH$60,000.$ The estimated useful of the asset was $4$ years and it had a residual value of GH$4,000.$ It was estimated that the equipment will produce $4,000$ units during its life. The financial year of Fred Limited ended on $31$st December $2023.$

You are required to calculate the amount of depreciation to charge for $31$st December $2021,2022$ and $2023$ using:

$($a$)$ The straight line depreciation method

$($b$)$ The reducing balance method

$($c$)$ Explain why it is important to distinct revenue expenditure and capital expenditure.