(10%) 4. Consider the defender-challenger data. Defender marginal costs for the remaining years Year 1 S1500 2 1650 3 1800 4 1850 5 4000 6 4500 7 5000 challenger first cost $10,000 500 600 800 1000 1200 1400 Year 7 cost 1600 46 year 1 cost year 2 cost year 3 cost year 4 cost year 5 cost year 6 cost 66 66 THE CHALLENGER HAS NO SALVAGE VALUE DURING ANY YEAR. The stated MARR is 10%. a) Calculate the economic life and the minimum AWC for the challenger. b) How long the defender should be kept in service before replacement? (10%) 4. Consider the defender-challenger data. Defender marginal costs for the remaining years Year 1 S1500 2 1650 3 1800 4 1850 5 4000 6 4500 7 5000 challenger first cost $10,000 500 600 800 1000 1200 1400 Year 7 cost 1600 46 year 1 cost year 2 cost year 3 cost year 4 cost year 5 cost year 6 cost 66 66 THE CHALLENGER HAS NO SALVAGE VALUE DURING ANY YEAR. The stated MARR is 10%. a) Calculate the economic life and the minimum AWC for the challenger. b) How long the defender should be kept in service before replacement