 1. Suppose unit gasoline (total km for each liter gasoline) is not constant but gradually reduced at a constant rate by the increasing number of total distance. Can you formulate the unit gasoline? How is the influence of the constant rate?
2. If the driver cost in increase by experience (depending on the number of years of working). How do you formulate the driver salary per month and how it affects the feasibility study?
3. The number of buses needed in the system, N is simply the average of maximum demand (number of potential passengers) divided by the passenger per cycle of one bus. Suppose you know the demand, how do you extend the formulation above for N number of buses? [Some administrative cost will not increase much by the additional number of buses]
4. If the fare is flat for passenger per cycle, is this fare system feasible? [Assume that people who go will eventually come back, thus the fare is divided by two]
5. If the salvage value decline linearly until zero in 10 years. How will it affect the feasibility study?
6. How sensitive is the system against externalities such as change of both interest rate and gasoline price?

Preferable reference for this tutorial is

Teknomo, Kardi (2006) Tutorial on Feasibility Study http://people.revoledu.com/kardi/tutorial/What-If-Analysis/index.html