The annual worth values for a defender, which can be replaced with a similar used asset, and a challenger are estimated in the table below. If the defender cannot be retained for more two years, and the challenger cannot be retained for less than 2 years. At an interest rate of 16% per year and over a study period of exactly 5 years, determine when the defender should be replaced. If number of years retained is AW value, AED per Year Defender Challenger 1 -14,000 2 - 13,700 |--18,000 3 - 16,900 --13,800 4. -17,000 -15,600 N -18.000 -17 500 Please note that the AW value in the table is over the number of years retained; for example, the defender AW of -16,900 is the annual cost for three years retention period etc