Is x less than y? (1) x-y+1<0 (2) x-y-1<0

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Is x less than y? (1) x-y+1<0 (2) x-y-1<0 [#permalink]

26 Feb 2011, 16:40

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Is x less than y?

(1) x-y+1<0
(2) x-y-1<0

[Reveal] Spoiler: OA

Last edited by Bunuel on 07 Aug 2012, 00:30, edited 1 time in total.

Edited the question and added the OA.

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Re: Is x less than y? (1) x-y+1<0 (2) x-y-1<0 [#permalink]

26 Feb 2011, 16:47

Is x less than y?

Is x<y? --> is x-y<0?

(1) x-y+1<0 --> x-y<-1. Sufficient.
(2) x-y-1<0 --> x-y<1. Not sufficient.

Answer: A.
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Re: Is x less than y? (1) x-y+1<0 (2) x-y-1<0 [#permalink]

28 Feb 2011, 18:32

yes A it is

1.) x-y<-1 This is satisfied when x<y

2.) x-y<+1 Not sufficient

example x=1.5 and y=1; 1.5-1 < 1
x = - 2 and y= -1; -2 - (-1) < 1

A it is.

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Can someone help on a tricky DS question on Inequalities [#permalink]

06 Aug 2012, 18:52

Is x less than y?
(1) x-y+1<0
(2) x-y-1<0

The official answer is a but as per my solution it should be d.

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Re: Can someone help on a tricky DS question on Inequalities [#permalink]

06 Aug 2012, 19:08

gagan_g2k wrote:

Is x less than y?
(1) x-y+1<0
(2) x-y-1<0

The official answer is a but as per my solution it should be d.

That's a very easy trap to fall for, I to fell for it.
Added the two inequalities and got x-y <0 and condluded both are necessary
But if you look at x-y +1 < 0 this means that x+y < -1
which means that X-Y < 0 as -1 < 0 , so we can get the answer from one only.

Now looking at 2) X-Y -1< 0 this means that x-y < 1 which doesn,t clearly mean that x<y as something less than 1 can be positive and negative both.

So A is the answer.
Damn i need more practice !

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Re: Can someone help on a tricky DS question on Inequalities [#permalink]

06 Aug 2012, 22:26

gagan_g2k wrote:

Is x less than y?
(1) x-y+1<0
(2) x-y-1<0

The official answer is a but as per my solution it should be d.

(1) x-y+1<0 implies x-y<-1<0, which means x-y<0 or x<y.
Hence sufficient.

(2) Take x = y = 0 for which obviously x is not less than y, but (2) holds. For x = 0 and y = 1, (2) still holds, but now x < y.
Not sufficient.

Answer A.
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Re: Can someone help on a tricky DS question on Inequalities [#permalink]

07 Aug 2012, 00:35

gagan_g2k wrote:

Is x less than y?
(1) x-y+1<0
(2) x-y-1<0

The official answer is a but as per my solution it should be d.

Merging similar topics. Please refer to the solutions above.

Next, please hide OA under the spoiler!

And most importantly, please read carefully and follow: rules-for-posting-please-read-this-before-posting-133935.html
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Re: Can someone help on a tricky DS question on Inequalities [#permalink] 07 Aug 2012, 00:35

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