5pts An earthmowing contractor is evaluating whether to use a larger excavator to rechuce current operating costs. The excavator can be purchased at $135,000 and is expected to have s usefvi uif eif 5 years after which it can be sold for $25,000. The optimititic most thely, and pestimistic profections of annual savings in operating costs are $40,000,$30,000, and $14,000, respecthvely. Uhe the cunter of estimates method to compute the mean annual savings, and then determine the present worth of purchasing this excavator at 7% interest