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.

Mountain Pass Canning Company has determined that any one of five machines can be used in one phase of its canning operation. The costs of the machines are estimated below, and all machines have an infinite life, if the minimum attractive rate of return is 20% per year, determine the machine that should be selected on the basis of incremental rate of return analysis. Machine First Cost, S 1 -310,000 2-280,000 3-345.000 4-480,000 5 -410,000 Annual Operating Cost, S/yr -180,000 -195,000 170,000 -120,000 -155,000