Inequality again

This topic has expert replies
User avatar
Legendary Member
Posts: 504
Joined: Tue Apr 19, 2011 1:40 pm
Thanked: 114 times
Followed by:11 members

Inequality again

by knight247 » Tue Aug 23, 2011 6:55 am
Is ax>bx?
(1)a>b
(2)a+x>b+x

Don't have an OA. Detailed explanations would be appreciated.

User avatar
Master | Next Rank: 500 Posts
Posts: 324
Joined: Mon Jul 05, 2010 6:44 am
Location: London
Thanked: 70 times
Followed by:3 members

by kmittal82 » Tue Aug 23, 2011 7:04 am
Is ax > bx
Or, rephrasing

Is x(a-b) > 0
This true under 2 conditions:

x>0 AND a>b
OR
x<0 AND a<b

In either case, we need both the value of x and the relationship between a and b to determine the answer to the inequality

(1)
Tells us a>b, but nothing about x, not sufficient

(2)
Same as (1), i.e. a>b

Combining (1) and (2) is pointless, since both give the same result

Hence, I think its (E)

Senior | Next Rank: 100 Posts
Posts: 47
Joined: Wed Sep 03, 2008 11:18 pm
Thanked: 5 times
Followed by:1 members

by top_business_2011 » Tue Aug 23, 2011 7:17 am
knight247 wrote:Is ax>bx?
(1)a>b
(2)a+x>b+x

Don't have an OA. Detailed explanations would be appreciated.
Required: ax>bx?

= ax-bx>0
= x(a-b)>0
The above inequality is valid under the following conditions: When X>0 and a-b>0, which implies a>b, or when x<o and a-b<0. So the question is basically to see whether the statements satisfy any of these conditions.

Statement 1: only a>b, without giving any idea about X. So Insufficient.
Statement 2: a+x>b+x = a+x-b-x>0 =a-b>0 = a>b. This statement gives a different version of the first statement. Hence Insufficient.

Both: No additional info., as both statements are equivalent.

Hence, the answer is E.