2.2.1 A Simple Model and a Textbook Solution

Using the information provided, Professor Tapia was able to write this simple mathematical model of the real world problem:

(2.2)

Professor Tapia set up the model as follows. He computed the number on the right-hand side of each equation by subtracting the departure time provided on the schedule from the arrival time. The time in Geneva is D hours ahead of the time in New York. In order to get the arrival time in Geneva that is on the schedule, we must add the flight time plus D hours to the stated departure time. For the return flight, D hours must be subtracted from the actual time in flight.

Using a simple method such as substitution or elimination, we can quickly determine that the time in flight, T, is hours and the time correction required to take into account the time zones crossed, D, is . We can check that our solution really satisfies (2.2) by substituting the values of T and D into the original linear system.

* The authors want to emphasize to the reader that this problem is not fictional and is and example of a real scenario that was formulated and solved using a system of linear equations.