IMO A.
Working backwards:
choice 2 is clearly insufficient. m can be 2 and n can be 3 or m can be 4 and n can be 3.
Choice 1 tells us that m - 1 and n + 1 are consecutive. The only way this could be possible if n becomes m and m becomes n.
lets take m = 10, n = 9
m-1 = 9
n+1 = 10
now we have 9 and 10 which are still consecutive integers. M has to be > n b/c it moves backwards one unit, otherwise it will move two units forward which will not make m and n consecutive.
(A)
Consequtive integers
This topic has expert replies
Source: Beat The GMAT — Data Sufficiency |
-
ssmiles08
- Master | Next Rank: 500 Posts
- Posts: 472
- Joined: Sun Mar 29, 2009 6:54 pm
- Thanked: 56 times
yes abhinav85,abhinav85 wrote:Hey Ssmiles
lets take m = 0, n = -1
m-1 = -1
n+1 = 0
the question says "If m and n are consecutive positive integers, is m greater than n?
I changed my numbers before you could post your post.
It still works out to be the same though.-
rah_pandey
- Master | Next Rank: 500 Posts
- Posts: 122
- Joined: Fri May 22, 2009 10:38 pm
- Thanked: 8 times
- GMAT Score:700
m and n are consecutive
let m<n
m-1+1=n+1
m-0=n+1
=>n=m-1=>m-n=1 a contradiction
since m<n is assumption
let m>n
n+1=m-1-1=n+1
n=m-3
m-n=3
correct...
therefore A is sufficient
if m is even=> n is odd
cannot say which is greater
therefore A
let m<n
m-1+1=n+1
m-0=n+1
=>n=m-1=>m-n=1 a contradiction
since m<n is assumption
let m>n
n+1=m-1-1=n+1
n=m-3
m-n=3
correct...
therefore A is sufficient
if m is even=> n is odd
cannot say which is greater
therefore A
