GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 19 May 2019, 17:38

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# If x>y, then is 1/x < 1/y?

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 17 Oct 2016
Posts: 261
Location: India
Concentration: General Management, Healthcare
GMAT 1: 640 Q40 V38
GMAT 2: 680 Q48 V35
GPA: 3.05
WE: Pharmaceuticals (Health Care)
If x>y, then is 1/x < 1/y?  [#permalink]

### Show Tags

28 Nov 2018, 10:01
1
1
00:00

Difficulty:

45% (medium)

Question Stats:

66% (01:41) correct 34% (01:23) wrong based on 64 sessions

### HideShow timer Statistics

If x>y, then is 1/x < 1/y?

A. x is negative

B. y is negative

_________________
_____________________
Chasing the dragon
Senior Manager
Joined: 14 Feb 2018
Posts: 390
Re: If x>y, then is 1/x < 1/y?  [#permalink]

### Show Tags

28 Nov 2018, 21:30
A) x is negative.
Case 1: x = neg y = neg, eg.x = -3, y = -5. Answer would be YES.
Case 2: x = neg y = pos ....but wait if this happens then x cannot be greater than y. Thus, discard case 2.

A is sufficient.

B) case 1: similar like that in A)..yes
Case 2: x = pos y = neg
x = 3 y = -5
This doesn't satisfy our condition. So, No for this case. Therefore, not sufficient.

Hence, A.

Posted from my mobile device
CEO
Joined: 12 Sep 2015
Posts: 3716
Re: If x>y, then is 1/x < 1/y?  [#permalink]

### Show Tags

29 Nov 2018, 17:52
Top Contributor
fitzpratik wrote:
If x>y, then is 1/x < 1/y?

A. x is negative
B. y is negative

Here's another approach....

Given: y < x

Target question: Is 1/x < 1/y?

Statement 1: x is negative
Since we already know that y < x, we can conclude that y is also NEGATIVE
If x and y are both NEGATIVE, then the product xy is POSITIVE
Since xy is POSITIVE, we can safely take the target question,Is 1/x < 1/y?, and multiply both sides by xy.
When we do so, we get the NEW target question: Is y < x?
Since it's given that y < x, the answer to the NEW target question is YES, y IS less than x
Since we can answer the NEW target question with certainty, statement 1 is SUFFICIENT

Statement 2: y is negative
There are several values of x and y that satisfy statement 2. Here are two:
Case a: x = -1/3 and y = -1/2. In this case, 1/x = -3 and 1/y = 2. So, the answer to the target question is YES, 1/x is NOT less than 1/y
Case b: x = 1/2 and y = -1/2. In this case, 1/x = 2 and 1/y = -2. So, the answer to the target question is NO, 1/x is NOT less than 1/y
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

RELATED VIDEO FROM OUR COURSE

_________________
Test confidently with gmatprepnow.com
Manager
Joined: 19 Apr 2017
Posts: 78
Concentration: General Management, Sustainability
Schools: ESSEC '22
GPA: 3.9
WE: Operations (Hospitality and Tourism)
Re: If x>y, then is 1/x < 1/y?  [#permalink]

### Show Tags

17 Apr 2019, 12:22
From the question stem
$$\frac{1}{x}-\frac{1}{y}<0$$ -> $$\frac{y-x}{xy}<0$$?
since $$x>y$$ -> $$(y-x)<0$$ then $$\frac{negative}{xy}<0$$

Two cases

$$\frac{negative}{positive}<0$$
$$\frac{negative}{negative}$$ becomes positive

Simplified question stem is xy>0 (or simpler question stem does x & y have same signs?)

a) x is negative,
y must also be negative as x>y so sufficient

b) y is negative
since x>y
x can be positive, then NO
x can be negative then Yes
Not sufficient.

Re: If x>y, then is 1/x < 1/y?   [#permalink] 17 Apr 2019, 12:22
Display posts from previous: Sort by