Do not use excel please !!!

The present worth of the cash flows through year k, PW, for a defender (three-year remaining useful life) and a challenger (five- year useful life) are given in the following table: PW of cash flows through year k, PWK Year Defender -19620 Challenger -15040 1 2 -35575 -27100 -42015 3 -48150 -64000 4 5 -87910 Please answer the following questions and attach your handwritten solutions in the next part. Assume that MARR is 10% per year. a) What is the economic service life for both the defender and the challenger, interpret the result based on the ESLS? Answer: b) When should we replace the defender if we use a fixed 5-vear planning horizon? The present worth of the cash flows through year k, PW, for a defender (three-year remaining useful life) and a challenger (five- year useful life) are given in the following table: PW of cash flows through year k, PWK Year Defender -19620 Challenger -15040 1 2 -35575 -27100 -42015 3 -48150 -64000 4 5 -87910 Please answer the following questions and attach your handwritten solutions in the next part. Assume that MARR is 10% per year. a) What is the economic service life for both the defender and the challenger, interpret the result based on the ESLS? Answer: b) When should we replace the defender if we use a fixed 5-vear planning horizon