50 animals competed for prizes at a certain fair. How many of the anim

Because some "animals" are not "cows". An animal might be a parrot or a donkey or an iguana or a fish. That's not something a question needs to tell a test taker.


If Statement 1 said "100% of animals won prizes", it would be sufficient. But it doesn't say that. It only talks about some of the animals, the cows.

If someone did assume all 50 animals were cows, that person would be assuming something you don't know to be true; you don't know how all the animals are cows. So that person would be using more information than the question provides, and would thus be making a logical mistake.


Statement 1 can't use 99%, since that's mathematically impossible with only 50 animals in total (you'd get a decimal number of cows, which is impossible).

If there were only 1 animal in total, Statement 2 wouldn't make any sense. Statement 1 alone would be sufficient in that case, because there can't be zero cows (it doesn't make sense to say "100% of cows won prizes" if there are no cows at all). So you could then conclude that the one animal in question is a cow, and that it won a prize. But you'd never see that situation on the GMAT, so there's no reason to worry about it.