Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 24 Aug 2016, 18:45

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# M02 Q14, what if the X and y are negative?

Author Message
Intern
Joined: 17 Feb 2008
Posts: 28
Followers: 0

Kudos [?]: 18 [1] , given: 5

M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

05 Mar 2009, 00:15
1
KUDOS
1
This post was
BOOKMARKED
$$x$$ and $$y$$ are positive integers and $$x > y$$ . What is the value of $$xy^2 + yx^2$$ ?

1. xy = 6
2. x is a prime number

[Reveal] Spoiler: OA
C

Source: GMAT Club Tests - hardest GMAT questions

$$xy^2+ yx^2 = xy(x+y)$$

* From S1, we know that $$xy=6$$ , but we do not know what is $$x+y$$ . Insufficient
* From S2, we know that $$x$$ is a prime number, but there is no information about $$y$$ . Insufficient

Combining the statements, we know that $$xy=6$$ . So $$x$$ is a prime number and $$x>y$$ , therefore $$y=2$$ . The problem can then be solved.

----------------------------------------------------------
But what happens if X & Y are negative as thats a possbility? So the answer must be E
SVP
Joined: 29 Aug 2007
Posts: 2492
Followers: 66

Kudos [?]: 692 [0], given: 19

Re: m02. Q14, what if the X and y are negative? [#permalink]

### Show Tags

05 Mar 2009, 06:20
Forrester300 wrote:
$$x$$ and $$y$$ are positive integers and $$x > y$$ . What is the value of $$xy^2 + yx^2$$ ?

1. xy = 6
2. x is a prime number

(C) 2008 GMAT Club - m02#14

* Statement (1) ALONE is sufficient, but Statement (2) ALONE is not sufficient
* Statement (2) ALONE is sufficient, but Statement (1) ALONE is not sufficient
* BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient
* EACH statement ALONE is sufficient
* Statements (1) and (2) TOGETHER are NOT sufficient

$$xy^2+ yx^2 = xy(x+y)$$

* From S1, we know that $$xy=6$$ , but we do not know what is $$x+y$$ . Insufficient
* From S2, we know that $$x$$ is a prime number, but there is no information about $$y$$ . Insufficient

Combining the statements, we know that $$xy=6$$ . So $$x$$ is a prime number and $$x>y$$ , therefore $$y=2$$ . The problem can then be solved.

----------------------------------------------------------
But what happens if X & Y are negative as thats a possbility? So the answer must be E

2 things to note:

1. x and y are +ves
2. x is a prime, which can never be -ve.

hth
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Senior Manager
Joined: 18 Aug 2009
Posts: 303
Followers: 3

Kudos [?]: 229 [0], given: 9

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

10 Nov 2009, 22:50
The solution can be reached even if X>Y not given (because value of X is not asked, so it doesn't matter as long as we find out that X can be either 2 or 3 and depending on the value of X, Y can be one of 2 or 3).
So unless "X>Y" is meant to be a red herring, it can be removed from the Q.
Senior Manager
Joined: 01 Feb 2010
Posts: 267
Followers: 1

Kudos [?]: 53 [0], given: 2

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

18 Mar 2010, 07:26
Forrester300 wrote:
$$x$$ and $$y$$ are positive integers and $$x > y$$ . What is the value of $$xy^2 + yx^2$$ ?

1. xy = 6
2. x is a prime number

[Reveal] Spoiler: OA
C

Source: GMAT Club Tests - hardest GMAT questions

$$xy^2+ yx^2 = xy(x+y)$$

* From S1, we know that $$xy=6$$ , but we do not know what is $$x+y$$ . Insufficient
* From S2, we know that $$x$$ is a prime number, but there is no information about $$y$$ . Insufficient

Combining the statements, we know that $$xy=6$$ . So $$x$$ is a prime number and $$x>y$$ , therefore $$y=2$$ . The problem can then be solved.

----------------------------------------------------------
But what happens if X & Y are negative as thats a possbility? So the answer must be E

Its C. explanation given above.
It is given that x & y are (+)ve.
Intern
Joined: 30 Jul 2009
Posts: 20
Followers: 0

Kudos [?]: 4 [0], given: 3

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

18 Mar 2010, 10:24
Well.. Q is saying, X and Y is +ve and they are both integers and X>Y.

ST 1 is XY=6, X could be either 6 and Y=1 OR x=3 and Y=2

so its insuff

ST 2... we dont know anything about Y or any value for any of X or Y... insuff

Together x has to be 3 and Y is 2... suff

Ans C
Senior Manager
Joined: 13 Dec 2009
Posts: 263
Followers: 10

Kudos [?]: 175 [0], given: 13

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

19 Mar 2010, 07:29
Question is saying that both the numbers are positive integers, so there is no question of considering the case when they are negative.
_________________

My debrief: done-and-dusted-730-q49-v40

Manager
Joined: 03 Aug 2010
Posts: 106
GMAT Date: 08-08-2011
Followers: 1

Kudos [?]: 58 [0], given: 63

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

22 Mar 2011, 05:57
Question stem reworded: What's the value of XY (Y + X) when x & Y are positive integers and x > y?

1) xy = 6. We still need to determine (Y+X) (insufficient)

2) X is prime. X can be 2, 3, 5, 7, etc and we know nothing of Y (insufficient)

1 and 2) Together, xy=6. Therefore x or y has to be an even integer. Since x is prime and larger than Y, X has to be 3 and Y 2. Both statements together provide that Xy(Y+X) = 30

Ans: C
Senior Manager
Joined: 01 Nov 2010
Posts: 295
Location: India
Concentration: Technology, Marketing
GMAT Date: 08-27-2012
GPA: 3.8
WE: Marketing (Manufacturing)
Followers: 10

Kudos [?]: 73 [0], given: 44

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

22 Mar 2011, 06:02
ANS IS C.

XY(X+Y)=?

ON COMBINING TWO STATEMENTS;
XY=6
AND X IS PRIME AND X>Y; ONLY 3 SATISFIES BOTH CONDITION.
SO, X=3, Y=2

ONE CAN FIND THE ANS AS 30.
_________________

kudos me if you like my post.

Attitude determine everything.
all the best and God bless you.

SVP
Joined: 16 Nov 2010
Posts: 1673
Location: United States (IN)
Concentration: Strategy, Technology
Followers: 34

Kudos [?]: 470 [0], given: 36

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

22 Mar 2011, 07:10
xy^2 + yx^2

= xy(X+y)

(1) xy = 6, so x = 6 and y = 1, or x = 3 and y = 2, (x+y) is different, so not sufficient.

(2) x is prime, but no information about y, so not sufficient.

From (1) and (2), x = 3, y = 2, so sufficient.

_________________

Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)

GMAT Club Premium Membership - big benefits and savings

Manager
Status: Seeking new horizons...
Joined: 03 Sep 2010
Posts: 64
Location: Taiwan
Concentration: Strategy, Technology
Followers: 2

Kudos [?]: 24 [0], given: 29

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

22 Mar 2011, 21:43
If they state that x and y are negative integers, x cannot be a prime number.

Thus the question would become invalid.

~Nilay
_________________

Learn to walk before you run.

Intern
Joined: 13 Mar 2012
Posts: 2
Followers: 0

Kudos [?]: 0 [0], given: 0

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

26 Mar 2012, 09:50

if notice that that statement one gives you (x)(y)=6

then you can see that the only factors for 6 is (1)(6) and (2)(3)
for X to be greater than Y. you will need x to be either 6 or 3

Now the second statement tells you that x is prime leaving us with the possibility of 3.
Intern
Joined: 20 Dec 2011
Posts: 19
Followers: 0

Kudos [?]: 2 [0], given: 2

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

26 Mar 2012, 12:18
Easy one from the GMATCLUB which rarely happens. Such questions really motivate you if face such questions after doing many wrong.
Manager
Joined: 15 Aug 2012
Posts: 111
Location: India
Concentration: Technology, Strategy
Schools: Merage '15 (A)
GPA: 3.6
WE: Consulting (Computer Software)
Followers: 6

Kudos [?]: 47 [0], given: 22

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

27 Mar 2013, 05:13
x and y are positive integers and x>y . What is the value of xy2 + yx2 ?

1. xy = 6
2. x is a prime number

For Case 1:
xy = 6 and x>y, has two solution x,y = {3,2 and 6,1}
for 3,2 the value is 12 + 18 = 30
for 6,1 the value is 6 + 36 = 42

For Case 2:
x is prime=> x can be 2,3,5
and y can have any value so the equation has infinite values.

Combining case 1 and 2:
The only possible solution for x,y is 3,2 and the equation solves to 30.

Hence C.
Intern
Joined: 11 Mar 2013
Posts: 8
Followers: 0

Kudos [?]: 6 [1] , given: 11

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

27 Mar 2013, 05:29
1
KUDOS
Can anyone tell the aproximate level of this question?

Intern
Joined: 27 Oct 2011
Posts: 15
Concentration: Finance, Technology
GMAT Date: 04-10-2012
Followers: 0

Kudos [?]: 18 [0], given: 7

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

27 Mar 2013, 05:45
Solution C

1) xy = 6

Considering x>y, below two scenarios can come up
a) x = 6
y = 1
Putting the above x & Y values in the equuation xy2+ yx2 = 6+36 = 42

b) x = 3
y = 2
Putting the above x & Y values in the equuation xy2+ yx2 = (3*4)+(2*9) = 40

Two solutions so 1 itself is not sufficient.

2) x is a prime number

x can be anything 1,3,5, 7.. so as y. not sufficient

Taking 1 & 2 together
XY = 6, X is a prime number & X >Y we get unique values for X & Y

i.e. X=3 & Y = 2, this will get you the unique solutin of the equation xy2+ yx2
Manager
Joined: 12 Dec 2012
Posts: 230
GMAT 1: 540 Q36 V28
GMAT 2: 550 Q39 V27
GMAT 3: 620 Q42 V33
GPA: 2.82
WE: Human Resources (Health Care)
Followers: 4

Kudos [?]: 75 [0], given: 181

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

27 Mar 2013, 06:36
chose A ... x+y is not known but has a fixed value .... therefore sufficient . Can anybody please explain why this cannot be correct?
_________________

My RC Recipe
http://gmatclub.com/forum/the-rc-recipe-149577.html

My Problem Takeaway Template
http://gmatclub.com/forum/the-simplest-problem-takeaway-template-150646.html

Math Expert
Joined: 02 Sep 2009
Posts: 34420
Followers: 6251

Kudos [?]: 79415 [2] , given: 10016

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

27 Mar 2013, 06:50
2
KUDOS
Expert's post
TheNona wrote:
chose A ... x+y is not known but has a fixed value .... therefore sufficient . Can anybody please explain why this cannot be correct?

When a DS question asks about the value of some variable (or an expression with variable(a)), then the statement(s) is sufficient ONLY if you can get the single numerical value of this variable (expression).

x and y are positive integers and x > y . What is the value of xy^2 + yx^2 ?

What is the value of $$xy^2 + yx^2=xy(y+x)$$?

(1) xy = 6 --> $$xy(y+x)=6(y+x)$$. Now, since x and y are positive integers and x > y, then from xy = 6 it follows that x=6 and y=1 OR x=3 and y=2, thus 6(y+x)=42 or 6(y+x)=30. Two different values, thus this statement is NOT sufficient.

(2) x is a prime number. Clearly insufficient.

(1)+(2) Since from (2) we know that x is a prime number, then x=3=prime and y=2, thus 6(y+x)=42. Sufficient.

Hope it's clear.
_________________
Math Expert
Joined: 02 Sep 2009
Posts: 34420
Followers: 6251

Kudos [?]: 79415 [0], given: 10016

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

27 Mar 2013, 06:54
Recobita wrote:
Can anyone tell the aproximate level of this question?

I'd say the difficulty level is ~600.
_________________
Manager
Joined: 12 Dec 2012
Posts: 230
GMAT 1: 540 Q36 V28
GMAT 2: 550 Q39 V27
GMAT 3: 620 Q42 V33
GPA: 2.82
WE: Human Resources (Health Care)
Followers: 4

Kudos [?]: 75 [0], given: 181

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

27 Mar 2013, 07:15
Bunuel wrote:
TheNona wrote:
chose A ... x+y is not known but has a fixed value .... therefore sufficient . Can anybody please explain why this cannot be correct?

When a DS question asks about the value of some variable (or an expression with variable(a)), then the statement(s) is sufficient ONLY if you can get the single numerical value of this variable (expression).

x and y are positive integers and x > y . What is the value of xy^2 + yx^2 ?

What is the value of $$xy^2 + yx^2=xy(y+x)$$?

(1) xy = 6 --> $$xy(y+x)=6(y+x)$$. Now, since x and y are positive integers and x > y, then from xy = 6 it follows that x=6 and y=1 OR x=3 and y=2, thus 6(y+x)=42 or 6(y+x)=30. Two different values, thus this statement is NOT sufficient.

(2) x is a prime number. Clearly insufficient.

(1)+(2) Since from (2) we know that x is a prime number, then x=3=prime and y=2, thus 6(y+x)=42. Sufficient.

Hope it's clear.

yessssssssssssssssss ... I did not consider the option of 6& 1... only 2&3 . Thanks Bunuel
_________________

My RC Recipe
http://gmatclub.com/forum/the-rc-recipe-149577.html

My Problem Takeaway Template
http://gmatclub.com/forum/the-simplest-problem-takeaway-template-150646.html

Intern
Joined: 02 Nov 2012
Posts: 2
Followers: 0

Kudos [?]: 0 [0], given: 5

Re: M02 Q14, what if the X and y are negative? [#permalink]

### Show Tags

27 Mar 2013, 11:38
saratchandra wrote:
Solution C

1) xy = 6

Considering x>y, below two scenarios can come up
a) x = 6
y = 1
Putting the above x & Y values in the equuation xy2+ yx2 = 6+36 = 42

b) x = 3
y = 2
Putting the above x & Y values in the equuation xy2+ yx2 = (3*4)+(2*9) = 40

Two solutions so 1 itself is not sufficient.

2) x is a prime number

x can be anything 1,3,5, 7.. so as y. not sufficient

Taking 1 & 2 together
XY = 6, X is a prime number & X >Y we get unique values for X & Y

i.e. X=3 & Y = 2, this will get you the unique solutin of the equation xy2+ yx2

So far the best explanation-Thanks Dude.
Re: M02 Q14, what if the X and y are negative?   [#permalink] 27 Mar 2013, 11:38

Go to page    1   2    Next  [ 22 posts ]

Similar topics Replies Last post
Similar
Topics:
3 M26-25 If x and y are negative numbers 14 15 Sep 2013, 19:24
1 M02 Q18 Is the total number of divisors of x^3 a multiple 3 18 Jan 2013, 11:07
28 What is the number of integers from 1 to 1000 (m07q14) 18 12 Feb 2009, 23:16
40 m02#24 14 05 Nov 2008, 08:21
22 m02#8 16 03 Nov 2008, 16:24
Display posts from previous: Sort by

# M02 Q14, what if the X and y are negative?

Moderator: Bunuel

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.