please solve without excel

Part A: An engineer estimated the equivalent annual costs of a currently installed machine and a new machine to replace it as follows: Years Retained Defender EAC Challenger EAC 1 145,000 136,000 2 96,430 126,000 3 63,317 92,000 4 39,321 53,000 5 49,570 38,000 a) Determine the economic service lives of the defender and challenger. b) What should be the replacement decision? Decision 1: Replace the Defender Now Decision 2: Retain the Defender till the end of its useful life Decision 3: Retain the Defender for one more year then re-do the replacement analysis then? Please justify to receive the full point. c) The defender was bought three years ago for $350,000. The current value of that machine is $150,000. The market value of the machine after 1 year is going to be $100,000. The operation cost of this machine at year 1 (from now not from the date of purchase) is $75,000. The interest rate is 20%. Based on this was the engineer's calculation of the red number in the table correct? If no, then what should be the correct number? Part A: An engineer estimated the equivalent annual costs of a currently installed machine and a new machine to replace it as follows: Years Retained Defender EAC Challenger EAC 1 145,000 136,000 2 96,430 126,000 3 63,317 92,000 4 39,321 53,000 5 49,570 38,000 a) Determine the economic service lives of the defender and challenger. b) What should be the replacement decision? Decision 1: Replace the Defender Now Decision 2: Retain the Defender till the end of its useful life Decision 3: Retain the Defender for one more year then re-do the replacement analysis then? Please justify to receive the full point. c) The defender was bought three years ago for $350,000. The current value of that machine is $150,000. The market value of the machine after 1 year is going to be $100,000. The operation cost of this machine at year 1 (from now not from the date of purchase) is $75,000. The interest rate is 20%. Based on this was the engineer's calculation of the red number in the table correct? If no, then what should be the correct number