Disclaimer: This is rehashed from an article I wrote in August 2016 for GineersNow. Some parts are added or edited for clarity.
Perhaps you can recall a day in your college life wherein you were tasked to solve a certain engineering problem by the instructor. You all performed the problem and tried to compare answers. You see that you yielded the same answers, but the process or the solution of the other one is different in some ways. And yet, both of you got the correct answer. Both of you derived the answer from among many possible solutions.
This is the simplest proof that engineering problems can be solved in many ways. There can be different interpretations in a problem which result to difference in solutions.
It’s like this: you departed at the same point (the same given values) and arrived at the same destination (the same answer). You took the bus while the other rode his car on the way, while there may be the other one who took his bike. And each one of you may have traversed different routes on the way. All of you reached what needs to be reached – the correct answer – regardless of the mode and ways. And that’s what’s important – arriving to the right place.
It is universal in all math and computation problems. Say in fluid mechanics, you are required to get the discharge of the tank, and you were given with different values needed to solve the problem. An engineering student can opt to use the values he or she wants to arrive to the answer. There are no restrictions to which one is the right solution, because there are many.
If there’s one moral lesson you need to learn about this concept, it’s this: you can’t go running around and say that your solution is the only one correct, because there are no absolute solutions, only absolute answers. There is a difference.