John has a job that requires him to travel 3 of every 4 weeks. He has an annual budget and can travel either by train or by plaine. The airline on which he typically flies has a frequent traveler programme that reduces the cost of his tickets according to the number of milels he has flown in a given year. When he reaches 25000 kilometres, the airline will reduce the price of ticket by 25 percent for the remainder of the year. When he reaches 50000 kilometres, the airline will reduce the price by 50 percent for the remainder of the year.
Graphically illustrate john's budget line, with train kilometres on the vertical axis and plane kilometres on the horizontal axis.