Word Problem Analysis

You have a four-wheel drive all-terrain truck, and you need to make a 27 000-km trip. Each tire can be used for 12 000-km. The four tires of the truck are new, and you have five new tires in the back of the truck. How can you use the nine tires to complete the trip?

(MathPower11 Ch5-Rational Functions, Equations and Inequalities)

Practical?
This problem is not very practical. Although, it deals with tires on a truck and making a long trip, it has this really weird aspect of having to change the tires during the trip. The reason this problem is odd is because no one usually drives long enough in a single trip for new tires to wear out. Say you drive for eight hours a day at 100km/hour it would be over 33 days of driving. I feel that this problem would have a more practical aspect if it was a semi-truck because they may drive this many kilometers. But changing the problem to a semi-truck brings the problem to eighteen tires and not four being used at one time, so maybe this makes the problem more complicated than intended.

Memorable?
The only thing memorable about this problem is wasting time on a trip to constantly rotate and change tires on the shoulder of the highway.

Solvable?
Yes this problem is solvable in more than one way. There could be the issue of which solution is most efficient, meaning the least number of stops to change tires.

Can there different positions or interpretations?
As being someone who has car knowledge, I have an issue about driving for extended periods of time and at high speeds when the tires have different levels of wear. This is not only bad for the car but also not so safe. If the car was only front wheel drive or only rear wheel drive then we could have the two front tires at the same level of wear and the two back tires at the same level of wear. But with this problem, the truck is all-wheel drive so the tires should all be the same so the tires are balanced.

How would kids interpret it?
I think that kids would interpret it correctly. I don't think that there would be any major misunderstanding about what the problem is asking.

Is this problem strange?
Yes! This problem is quite strange, although there I'm sure exists stranger problems. This problem does relate to driving and lifespan of a tire in kilometers. I think this problem should not be worded as "you" have a truck... but rather that someone wants to make this trip and they have these tires etc.

Rewrite or Extend?
Since I have knowledge about cars and changing tires I would add to the question that the tires need to be as balanced as possible. Also, students may not be familiar with any of this if they do not drive or are not in automotive class.