Can someone answer this IQ question for me?

The answers are not part of the question, but they are part of the test. In my experience, these types of tests don’t rely on math knowledge, or at least anything beyond simple elementary math… I’m not saying square roots are advanced, but they want to test people of all ages on intelligence without requiring any knowledge, if that makes any sense.

But you can’t say that he likes “numbers whose first digit are one more than another number”, or the like, because every number meets that description. By your argument, he likes 400 but not 300, and also likes 300 but not 200, which doesn’t make any sense.

See, in my experience, squares are common in these types of tests. And these are all very simple squares.

Chronos, I see what you are saying but I also don’t see the problem. If the question was phrased “John likes 400 but not 300, he likes 300 but not 200…” it would give a clue as to what criteria John is using when liking one number over another, that he is choosing to like a number relative to another. But, in congruence to the gist of this thread, I suppose the answer is dependent on the author’s intentions.

Silver is fatal to werewolves. You guys should know that. And it’s actually a different color than aluminum and iron, so I’m not sure color is the correct property to use.

I don’t like color as the property, either, which is why I don’t think that’s what the test maker was going for, but how is the color that different from aluminum and iron? They’re all a gray sort of color, with a metallic sheen. I have a .999 silver coin in front of me, and I wouldn’t be able to tell you if it’s silver, aluminum, or iron just by looking at it. OK, I could probably rule out iron, because of the reflectivity, but not the color. That said, I suppose I couldn’t tell you it’s not white gold, either. All that stuff looks the same to me.

My first thought for the metal question is Gold, because it doesn’t readily oxidize. Aluminum, Silver, and Iron sure do. But, yeah, what a poorly framed question.

I’ve always seen silver as a definite white color, whereas iron and aluminum are much more grey.

IMO if the question was meant to be posed to elementary school kids, gold due to its color would be the answer the test writer meant.

If the same question was meant to be posed to middle or high school science students, iron due to ferromagnetism would be the answer the test writer meant.

For middle or high school history students, iron due to never being a preciously expensive metal would be the answer the test writer meant.

To grown-ups with graduate degrees, any answer is as defensible as any other. The problem comes when people with grad degrees are answering questions written by people who think like middle schoolers.

See, if my high school chemistry teacher gave the quiz, it’d definitely be about the chemical symbols. That’s my favorite answer of the bunch.

Silver oxidizes, but not readily. And aluminum oxidizes very readily, but only in an invisibly-thin surface layer that prevents the rest of it from oxidizing. Iron’s the only one of the lot that really does anything resembling rusting.

Then how come I have to polish my silver regularly?

You are removing Silver Sulfides, not Silver Oxides.

Apart from the aforementioned killing warewolves function, the number of letters in “silver” is a triangular number.

A few weeks ago, I took my bike in for its annual overhaul. The mechanic told me the frame was rusting and probably would need to be replaced in a year or so. My bike has an aluminum frame, so after thinking about it a while, I thought, “wait a minute, how can aluminum rust?” Well before calling the mechanic about it, I googled for aluminum corrosion. And guess what; it can corrode. Whether or not you call it “rust” like my mechanic did is more of a semantic issue.

Going back to the original question, I would say that John only likes numbers that can be expressed as (2^x)*(5^y). In that case 1000 is correct.

ETA: where x and y are integers, of course.

Bah! Thanks for the correction.

A little chemistry knowledge is a dangerous thing.

“John likes values of the form 3x + 1” seems to me as plausible a criterion as “John likes values of the form x^2”. Plausible enough to say the question is far from unambiguous.

“John likes values of the form x^2”: Answer must be 900
“John likes values of the form 3x + 1”: Answer must be 1000
“John likes values of the form 10000/x”: Answer must be 1000

Iron is the only one that is also a verb.

Aluminum is the only one that never forms part of a person’s surname (please someone prove me wrong :p).