6. 4.30 An electric switch manufacturing company has to choose one of three different assembly methods. Method A will have a first cost of

$40,000, an annual operating cost of $9000, and a service life of 2 years. Method B will cost $80,000 to buy and will have an annual operating cost of $6000 over its 4-year service life. Method C will cost

$130,000 initially with an annual operating cost of $4000 over its 8-

year life. Methods A and B will have no salvage value, but Method C will have some equipment worth an estimated $12,000. Which method should be selected using present worth analysis at a MARR of 10% per year?Page 132