Exercise 6-21B Annual versus cumulative data for replacement decision ( Appendix) Because their three adult children have all at last left home, Joseph and Audrey Peck recently moved to a smaller house. Joseph owns a riding lawnmower he bought three years ago to take care of the former house's huge yard; it should last another five years. With the new house's smaller yard, Joseph thinks he could hire someone to cut his grass for $800 per year. He wonders if this option is financially sound. Relevant information follows. Required a. What is the annual opportunity cost of using the riding mower? Based on your computations, recommend whether Joseph should sell it and hire a lawn service. b. Determine the total cost of hiring a lawn service for the next five years. Based on your computations, recommend whether Joseph should sell the mower and hire a lawn service