excel functions please

Question 2 15 pts Whitten Inc. will purchase a piece of soil clean up equipment for $125,000 and depreciate the equipment over four years using straight line depreciation to zero salvage value. The recovery equipment will generate revenues of $85,000/year and operating expenses of $17,500/year expressed in real dollars (constant dollars, today's dollars) for years 1-4. The average rate of inflation is 6%. The company's average tax rate is 45%. If the after tax MARR is 17%, what is the after tax Present Worth ? ans. $xxxx What is the real after tax internal rate of return ? ans. xx.x%