This reminds me of a Physics GRE I took. I studied all the tests and remember very clearly the test saying to only calculate to two decimal places to save time. There was a relativity question that had 3 answers that just varied on how many decimal places you carried through your calculations. That question had the answer if you kept 2. But it also had the answers for more. I'm not sure questions like this actually show that you know the material, considering to get 3 of the 5 answers you have to do the actual calculations.

What I learned about studying for tests like these was that you were studying for the test, not the material. This felt extremely different than studying for... say... an actual physics test.