A firm is evaluating an investment in a fleet of vehicles that will be used for $10$ years. The vehicles would cost $$70$ million. According to the IRS, the useful life of these vehicles is $5$ years, and the firm will depreciate them using straight line depreciation. The firm expects to generate additional revenue of $$30$ million per year using these vehicles. At the same time, the firm expects to pay approximately $$10$ million maintaining them. However, the firm anticipates being able to utilize them to aid in other endeavors, saving approximately $$5$ million per year. At the end of the $10$ year period, the firm expects to be able to sell the vehicles for $$10$ million. The company pays taxes at a $40\%$ rate. The firm anticipates that its cash needs will increase with the vehicles in use, so it plans to keep an additional $$20$ million in cash for the next $10$ years. What is the NPV of this investment if the firm has a $14\%$ cost of capital?

I am told the correct answer is $24\mathrm{.}91$ million, can you explain how to get this answer?