20. Comparing Mutually Exclusive Projects [LO1] Letang Industrial Systems Com pany (LISC) is trying to decide between two different conveyor belt systems. System A costs $265,000, has a four-year life, and requires $73,000 in prelax annual oper ating costs. System B costs $345,000, has a six-year life, and requires $67,000 in pretax annual operating costs. Both systems are to be depreciated straight-line to zero over their lives and will have zero salvage value. Whichever project is chosen, it will not be replaced when it wears out. If the tax rate is 34 percent and the discount rate is 8 percent, which project should the firm choose? 21. Comparing Mutually Exclusive Projects [L04] Suppose in the previous problem that the company always needs a conveyor belt system, when one wears out, it must be replaced. Which project should the firm choose now