GMAT Paper Test (Code 25, Q#14)
This topic has expert replies
Source: Beat The GMAT — Problem Solving |
- givemeanid
- Master | Next Rank: 500 Posts
- Posts: 277
- Joined: Sun Jun 17, 2007 2:51 pm
- Location: New York, NY
- Thanked: 6 times
- Followed by:1 members
Sum of those two numbers will be a multiple of 11. So, the answer would be any number that is not a multiple of 11.
So It Goes
-
samirpandeyit62
- Master | Next Rank: 500 Posts
- Posts: 460
- Joined: Sun Mar 25, 2007 7:42 am
- Thanked: 27 times
let M be "ab"
so N will be "ba"
hence we can say M = 10a + b
and N =10b + a
so M + N = 11a +11b
hence it is 11(a + b)
i.e sum will be 11 * (sum of the 2 digits)
hence it is a multiple of 11
but I see in the answers there are 3 choice which are muliples of 11
and 2 choices which are not i.e 16, 181
are u sure that there is no typo in the choices.
Regards
Samir
so N will be "ba"
hence we can say M = 10a + b
and N =10b + a
so M + N = 11a +11b
hence it is 11(a + b)
i.e sum will be 11 * (sum of the 2 digits)
hence it is a multiple of 11
but I see in the answers there are 3 choice which are muliples of 11
and 2 choices which are not i.e 16, 181
are u sure that there is no typo in the choices.
Regards
Samir
samirpandeyit62
i got the same answer as you - but I used instinct, POE and some plugging in to get there.
Should have used the equation instead - much faster and more reliable. Really appreciate your posts - am becoming a fan :)
i got the same answer as you - but I used instinct, POE and some plugging in to get there.
Should have used the equation instead - much faster and more reliable. Really appreciate your posts - am becoming a fan :)
-
samirpandeyit62
- Master | Next Rank: 500 Posts
- Posts: 460
- Joined: Sun Mar 25, 2007 7:42 am
- Thanked: 27 times
Thanks ri2007 for your compliments, but I dont really think I'm better than you or the many brilliant people around here, just trying to learn & extend any possible help from my side, Knowlege increases by sharing, I'm sharning mine & trying to gain from others over here. Thats how I look at it.
Thanks
Samir
Thanks
Samir

















