A little surprised at the percentages(40-60 at the time of writing). I think there is one thing we can know considering it is tagged as hard, but first things first: since it has no variables, we can eliminate D. On the test, we might not know what is hard, but we have an idea that as we get later into the math section, the difficulty increases. Therefore, we might suspect some trick. So even if we just used the calculator, we might be able to suspect when they are very close that C is a really good possibility. I give this long preface because I am making an assumption that anyone who could see, mostly likely in A, that the numerator's 135 has as a factor 15 and therefore can be re-written by making 9*15 under the radical, simplifying to 3 root 15 and then reduced just plain 3, got it right. The same can be done for the other one.