Certain questions on the GMAT can be solved rather quickly if you spot the Number Properties involved and you have the ability to pattern-match.
The 'key' to answering this question quickly is the knowledge that 'squaring a positive fraction makes the fraction SMALLER, while square-rooting a positive fraction makes the fraction BIGGER.'
Here is the proof:
(1/2)^2 = (1/2)(1/2) = 1/4
Squaring the positive fraction made the fraction SMALLER.
Root(1/4) = Root(1)/Root(4) = 1/2
Square-rooting the positive fraction made the fraction BIGGER.
With that knowledge, take a look at the first 3 answer choices to this question. The prompt asks which of the 5 answers is biggest (and we'll get to all of the answers in a moment). Which of the first 3 answer choices is biggest? Notice how all 3 have the same fractions - one answer square-roots them all, one leaves them as is, and one squares them all. You should be able to say definitively that Answer A is the largest of those 3.
Next, a bit of estimation will come in handy. Notice how Answer A ADDS 4 fractions that are all fairly close to 1.... so that total has to be a little less than 4.....
What do Answers D and E do....? Without doing the calculation, you should notice how BOTH answers subtract at least one fraction; by extension, there's no way that those 2 totals are close to 4.
GMAT assassins aren't born, they're made,
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