please good hand written

A high-speed electronic assembly machine was purchased two years ago for $35,000. At the present time, it can be sold for $10,500 and replaced by a newer model having a purchase price of $21,250; or it can be kept in service for up to three more years. The new assembly machine, if purchased, has a useful life of not more than four years. The projected resale values and operating and maintenance costs for the challenger and the defender are shown in the accompanying table on a year-by-year basis. If the MARR is 15%, answer the following questions: years. The projected resale values and operating and maintenance costs for the challenger and the defender are shown in the accompanying table on a year-by-year basis. If the MARR is 15%, answer the following questions: Year 0 1 2 3 Challenger Market Operation & Maintenance Value Costs $21,250 Na $15,500 $5,000 $12,500 $6,550 $11,000 $9,000 $9,500 $9,750 Defender Market Operation & Value Maintenance Costs $10,500 n/a $8.500 $7,000 $6,000 $8,500 $4,000 $9,500 $3,800 $13,000 4 a) (5 points) What is the Economic Life of the Challenger? b) (5 points) What is the Economic Life of the Defender? c) (15 points) Should the old model be replaced or not? If Yes, when and Why TN, why not