I wouldn't really worry about markup. A lot of the questions they ask aren't about markup, and the ones that are focusing on markup are incredibly easy - more like common sense. There is no "special formula" or "magic way" of doing markup. Just pretend you are part of a company or you are a consumer who is crunching numbers. it will make more sense if you try to do it without looking at any "sample" examples here on this forum. Just read it aloud to yourself and think it through. What makes the most sense to you is (probably) the correct answer! if you keep messing up on sample problems, look at it another way:
You have to remember - EVERYONE wants a good deal! But everyone also wants a PROFIT! Those two factors combined are what drives business to either success or failure.
That means even the manufacturer and middle guys want a piece of the pie. The consumer, though, has to be willing to pay that markup. Extremes are usually the wrong answer. I mean, yeah, there are markups out there that are 500% but in the REAL world (and on this test) it is usually around 50% - 150%. 200% at most, 20% at least. If you want to practice a little more with real life situations, go to JCPennys or Macys or even Walmart on a discount sale - with signs like 20% off, 50% off, 70% off. If you can count backwards, you can count forwards!
This skill isn't just something for a test. You can also use it to determine what tip you'll give the waiter of your table tonight during Father's Day.
Even cell phones these days have "automatic tip calculators" - this can also serve as practice examples where you can input any number and see what the amount would be in that scenerio.