Data Sufficiency

Hey guys,

I have been trying to decipher Prob 169 from the 2nd ED quant guide and its been driving me nuts.

Question:
where N is a positive integer;
N^2 is 72;
Identify the largest positive integer that must divide N;


I understand the explanation (more comsi, than comsa), but I am unsure if I can make all these assumptions on the test.

Any explanations from fellow Gmatters is much appreciated.

Thanks
KK

Please post the complete question. Someone will definitely come to your rescue..

Cheers!!

Is the answer 3?

N = 72 ^0.5
72 = 9 x 4 x 2
9^0.5 = 3

is it

6