I just don’t get it. I’ve asked around, but they don’t get it either.
John likes 400 but not 300; he likes 100 but not 99; he likes 2500 but not 2400. Which does he like?
900
1000
1100
1200
Extra points if you can tell me where I got it from 
1200, John always chooses the higher number (my WAG at least).
Bah, Opengrave. The list of likes and not-likes isn’t read as compared to each other - they are two complete lists. So in:
99
100
300
400
2400
2500
John likes 100, 400, and 2500. It’s not a highest number issue.
I’d say John likes perfect squares.
- Rick
Er… which means John likes 900 in the choices list offered above.
You rock 
I concur with Bricker. Though at first, I thought it had to do with divisibility by 3.
You got it from Zoom…though they use another name which I can’t recall at the moment.
You may be right, but I found it on an emode test. Hence my humiliation at not being able to get it.
More specifically, John likes numbers whose square root is evenly divisible by 10.
100 = 10[sup]2[/sup]
400 = 20[sup]2[/sup]
900 = 30[sup]2[/sup]
2500 = 50[sup]2[/sup]
A perfect square is actually a number whose square root is a whole number (1, 4, 9, 16…).
How can you make that statement with such assurity? As far as I can see, there is no inherent reason why Opengrave’s answer isn’t equally as valid as yours – viewing them as pairs of numbers seems perfectly acceptable without any more context to go by. The phrasing of the question is ambiguous. This is exactly why I hate IQ tests: several answers are often logically possiblle, but only one is considered “right”, often for no clear reason.
-b
That’s not true. Many questions on many IQ tests have several acceptable answers.
Did it say that he likes 400 better than 300? 100 better than 99? 2500 better than 2400? No, it said that he likes 400, 100, and 2500 and dislikes the others. Although one could imagine other answers to the question, perfect squares is what jumped out at me and the other answer is untenable on any reasonable reading.
I also thought it was divisible by three, although I like the squares answer as well. The preferring larger numbers answer is illogical given the context, eg, that likes and dislikes are not comparisons and not exclusive.
I always thought, for questions like this, that a singularly intelligent person would pick up on all these possibilities, but realize that the perfect squares one makes the most sense, given that it’s an IQ test question. (For instance, it makes more sense than divisibility by 3, because with that, both 900 and 1200 are valid answers.) Sometimes, intelligence means outsmarting the test-maker.
But, the stated numbers he doesn’t like are all divisible by 3, not the numbers he likes, so it could have been that he likes numbers not divisible by 3, in which case he’d not like 900 and 1200.
Since we’re asked which one of the possible answers is the one he likes, it’d have to be a different criteria for liking, perfect squares as it turns out.
(I took the emote test too, forget exactly what my rating was; wouldn’t mind seeing the reasoning they give for “correct” answers.)
Ooops, yeah, in my post, I should have said “both 1000 and 1100” instead of “both 900 and 1200”. I guess it’s clear how I’d do on a test like this…
I’m not trying to pick a fight here but after re-reading the OP we’re not asked which one he likes, we’re asked which he likes. There’s therefore no reason to exclude divisibility by three.
Personally, I think the bastards who dream this crap up should change the name from “IQ test” to “think like me test.” Having said that, my crackpot theory is that you’re interpretation is the measure for correctness. Their hoping that in this situation you’ll infer which really means which one. That and be able to swing a bit o’ math.
Can’t read, you get a point.
Ooh ooh, the Mensa online practice test. I’m a two-time veteran of said question - once online, and it actually showed up in the regular admittance test, too.
John could very well only like numbers that take the form 3x+1, because 3133+1=400, 333+1=100, and 3*833+1=2500.
Therefore, he must like 1000, because 3*333+1=1000, and no other choices take this form.
IQ test makers don’t seem to put much effort into weeding out alternative choices that they will deem to be “incorrect” even though logical.
The answer is 1000 because it is a perfect square.