Hi All,
This question has a great 'brute force' approach. Sometimes the big 'shortcut' that you'll find in a prompt is in the way that you organize your information. For this question, try writing the first 12 perfect squares VERTICALLY (instead of horizontally):
0
1
4
9
16
25
36
49
64
81
100
121
144
Looking at the numbers in this way, you can focus on the UNITS DIGITS, so it should be easier/faster to find the 4 answer choices that ARE the sum of perfect squares and the 1 that is NOT.
The first 3 answers are relatively small (and easy to spot):
36 = 0 + 36
37 = 1 + 36
65 = 1 + 64
The real work involves figuring out whether Answer D or E is the one that that you cannot get to.
If you start with the biggest number first - in this case, 144 - then there's clearly no number in the list that will get you to 146 or 147.
Next, try the 121....whatever you add to this number would need to have a 5 or a 6 as a units digit....25 is the match. Thus, you know that 146 IS possible while 147 must be the one that's not.
Final Answer:
GMAT assassins aren't born, they're made,
Rich