Engineering Economy - Do not use Excel functions for this problem, I need to know how to do the problem without them. If you use an Excel function, it will be of no help to me.

An engineer at Anode Metals is considering the projects below, all of which can be considered to last indefinitely. If the com pany's MARR is 14% per year, determine which two alternatives should be selected based on incremental rate of return analysis? Machine First Cost, S 20,000 10,000 -15,000 -70,000 -50,000 Annual Income, S/yr 3,000 2,000 2,800 10,000 6,000 Alternative's Rate of Return, % 15 18.7 4.3 12