positive int

This topic has expert replies
User avatar
Master | Next Rank: 500 Posts
Posts: 407
Joined: Tue Jan 25, 2011 9:19 am
Thanked: 25 times
Followed by:7 members

positive int

by Ozlemg » Thu Aug 04, 2011 1:40 am
a, b, and c are positive integers. If a, b, and c are assembled into the six-digit number abcabc,
which one of the following must be a factor of abcabc?
(A) 16
(B) 13
(C) 5
(D) 3
(E) none of the above

OA : B
The more you suffer before the test, the less you will do so in the test! :)
Source: — Problem Solving |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3835
Joined: Fri Apr 02, 2010 10:00 pm
Location: Milpitas, CA
Thanked: 1854 times
Followed by:523 members
GMAT Score:770

by Anurag@Gurome » Thu Aug 04, 2011 3:30 am
Ozlemg wrote:a, b, and c are positive integers. If a, b, and c are assembled into the six-digit number abcabc, which one of the following must be a factor of abcabc?
(A) 16
(B) 13
(C) 5
(D) 3
(E) none of the above

OA : B
The sin-digit integer abcabc can be written as 100000a + 10000b + 1000c + 100a + 10b + c = 100100a + 10010b + 1001c = 1001(100a + 10b + c)
Now from the given answer choices, check 1001 is divisible by which integer.
It can be seen that 1001 is divisible only by 13.

The correct answer is B.
Anurag Mairal, Ph.D., MBA
GMAT Expert, Admissions and Career Guidance
Gurome, Inc.
1-800-566-4043 (USA)

Join Our Facebook Groups
GMAT with Gurome
https://www.facebook.com/groups/272466352793633/
Admissions with Gurome
https://www.facebook.com/groups/461459690536574/
Career Advising with Gurome
https://www.facebook.com/groups/360435787349781/

Legendary Member
Posts: 1448
Joined: Tue May 17, 2011 9:55 am
Location: India
Thanked: 375 times
Followed by:53 members

by Frankenstein » Thu Aug 04, 2011 3:30 am
Hi,
abcabc = (1001)*abc
1001 = 13*11*7

Hence, B
Cheers!

Things are not what they appear to be... nor are they otherwise