Granny's Butter and Egg Business is such that she pays an effective tax rate of 40%. Granny

Question:

Granny's Butter and Egg Business is such that she pays an effective tax rate of 40%. Granny is considering the purchase of a new Throb Churn for $25,000. This churn is a special handling device for food manufacture and has an estimated life of 4 years and a salvage value of $5000. The new churn is expected to increase net income by $8000 per year for each of the 4 years of use. If Granny works with an after-tax MARR of 10% and uses MACRS depreciation, should she buy the churn?

Depreciation
Depreciation is an important concept in accounting. By definition, depreciation is the wear and tear in the value of a noncurrent asset over its useful life. In simple words, depreciation is the cost of operating a noncurrent asset producing... Salvage Value
Salvage value is the estimated book value of an asset after depreciation is complete, based on what a company expects to receive in exchange for the asset at the end of its useful life. As such, an asset’s estimated salvage value is an important... MARR
Minimum Acceptable Rate of Return (MARR), or hurdle rate is the minimum rate of return on a project a manager or company is willing to accept before starting a project, given its risk and the opportunity cost of forgoing other...