From this question that I just asked, I will also need help figuring out how to calculate the NPV if they keep the five big buses and don't get mini buses and the NPV if they get the 8 mini buses and use them for transporting students. This is the question that I just asked:

I need to understand how to calculate NPV in two scenarios. One is to sell 5 buses that have a value of $15,000 each and a life expectancy of 5 years. My answer would be the NPV is $15,000 x 5 = $75,000.

The second is Keep the buses to use for field trips and use 8 mini buses instead. What is the NPV for keeping the buses and getting mini buses? I don't understand which information is used to calculate this?

Mini buses cost $$27,000 each, have a life of 5 years (straight line depreciation). Annual charters for field trips is $30,000, keeping the big bus would cut that cost to $5,000. Annual bus driver salary is $18,000 so we would need three additional drivers. Annual cost of operating a full size bus is $50,000 annual cost of operating a mini bus is $20,000. Redesigning the bus route for using 8 mini buses is $15,250 (includes public notification etc.). The hurdle rate is 12%.

There are too many variables, I don't understand what I should use in these calculations.