Please explain all steps and show formulas. (no excel plots please)

Two alternatives are being considered. Alternative A, which as a life span of 5 years, costs $25,000 to purchase. It is estimated that M&O costs will be $1,000 in the first year and increase by $200 each year. Alternative B has a life span of 4 years and costs $40,000 to purchase. M&O costs for Alternative B will be $1,500 in the first year and increase by $100 each year. The revenues are expected to be $12,000 a year (beginning in year 1) for both alternatives. Given an interest rate of 8%, which alternative(s) should be selected if the alternatives are: (a) independent and (b) mutually exclusive