abcabc = a*100000 + b*10000 + c*1000 + a*100 + b*10 + c

1000(a*100 + b*10 + c) + (a*100 + b*10 + c)

1001(a*100 + b*10 + c)

prime factors of 1001 are 7, 11, 13

7, and 11 are not options, so I think it is 13.

(B)

Well done, Ssmiles.

OA: B

The important thing in the question is the order , if you spot this then no need to expand

order is abcabc I can write it as-----abc~abc ( two groups) the group to the left is 1000 times the group to the right

let abc = p

in other words abcabc = 1000p +p = 1001p , so if you know the factors of 1001 you know the answer what are the factor of 1001 ?

we know 11 is a factor ( 11*91) so are 7 and 13 (91=7*13)

Hence the answer is 13

what I see is that when one gets a question similar to this one it should be answerable with in 1 min so there must be a catch to the question
just think why did the question say abcabc ---- because something is there

If you see this the question becomes very easy

If you see this the question becomes very easy

Agree.

Part of GMAT is about spotting patterns(i.e. if one exists). If one is successful in doing so under exam pressure/timing then it becomes really easy and if not then it becomes difficult

Good luck, All!