I have been trying to figure this question out for my engineering economics class. I am trying to prepare for my exam coming up in a couple weeks this is one of the practice questions from a previous exam. I am not sure how to do it, any insight would be helpful. Thank you.

Problem 3. (25%) A company is considering purchasing a backhoe that will cost $110,000. It will last 6 years with a salvage value of $20,000 and will reduce maintenance and operating costs by $30,000. The after-tax MARR of the company is 9%, the CCA rate is 20% and the tax rate is 55%. a) What is the exact after-tax IRR for this investment? b) What is the approximate after-tax IRR? c) Should the company buy the backhoe