You can choose between two purchases: Machine A or Machine B. Machine A costs $18,000 and has a salvage value of $7,000 after 3 years. Machine B costs $25,000 and has a salvage value of $3,000 after 4 years. You can lease a Machine B equivalent for $4,000 per year, if you initially purchased Machine B. You need a machine for a total of 6 years, and can purchase a new machine in the future at the same price with the same salvage value. If i is 8% annual rate compounded annually, which machine should be purchased? Show work and justify answer.