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

It is currently 18 Sep 2018, 14:39

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

Is xy > 16?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 49206
Is xy > 16?  [#permalink]

Show Tags

New post 21 Feb 2016, 10:08
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

72% (00:42) correct 28% (00:37) wrong based on 330 sessions

HideShow timer Statistics

Intern
Intern
avatar
Joined: 15 Feb 2016
Posts: 10
Re: Is xy > 16?  [#permalink]

Show Tags

New post 21 Feb 2016, 10:58
Neither 1 nor 2 is sufficient. The x could be negative in either case 1 or 2. If x is negative and y is not, the product will surely be less than 16.
Intern
Intern
avatar
Joined: 27 Apr 2015
Posts: 13
GMAT ToolKit User
Re: Is xy > 16?  [#permalink]

Show Tags

New post 21 Feb 2016, 22:18
1
1
for xy > 16 , x and y should have similar signs.

1) 1 < |x| < 4 means that x can be either (-1.2,-1.3,-1.4.......,-3.9) or x can be (1.1,1.2,1.3....,3.9) and value of y is not provided hence not sufficient.

2) y > 16 provides us the value of y but we donot know the value of x. hence not sufficient.

Combining 1 and 2 we are not sure about the sign of x as x can be +ve or -ve.

Thus E is the answer.
Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 6204
GMAT 1: 760 Q51 V42
GPA: 3.82
Premium Member
Re: Is xy > 16?  [#permalink]

Show Tags

New post 21 Feb 2016, 22:20
Forget conventional ways of solving math questions. In DS, Variable approach is the easiest and quickest way to find the answer without actually solving the problem. Remember equal number of variables and independent equations ensures a solution.

Is xy > 16?

(1) 1 < |x| < 4
(2) y > 16


In the original condition, there are 2 variables(x,y), which should match with the number of equations. So you need 2 equations. However, for 1) 1 equation, for 2) 1 equation, which is likely to make C the answer. When 1) & 2), x=2, y=18 -> yes, x=-2, y=18 -> no, which is not sufficient.
Therefore, the answer is E.


 For cases where we need 2 more equations, such as original conditions with “2 variables”, or “3 variables and 1 equation”, or “4 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 70% chance that C is the answer, while E has 25% chance. These two are the majority. In case of common mistake type 3,4, the answer may be from A, B or D but there is only 5% chance. Since C is most likely to be the answer using 1) and 2) separately according to DS definition (It saves us time). Obviously there may be cases where the answer is A, B, D or E.
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $99 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Manager
Manager
avatar
B
Joined: 07 May 2015
Posts: 175
Location: India
GMAT 1: 660 Q48 V31
GPA: 3
GMAT ToolKit User
Re: Is xy > 16?  [#permalink]

Show Tags

New post 22 Feb 2016, 00:59
St1:
value of x can be anything from -1.1 to -3.9 or 1.1 to 3.9
and there is no clue about y
Insufficient

St:2 y>16
if x = 2 then xy = 32 > 16
if x = -2 then xy = -32<16
insufficient

St 1+2:
still value of x is not clear

This Ans: E
SVP
SVP
User avatar
D
Joined: 26 Mar 2013
Posts: 1805
Reviews Badge CAT Tests
Re: Is xy > 16?  [#permalink]

Show Tags

New post 22 Feb 2016, 03:36
Bunuel wrote:
Is xy > 16?

(1) 1 < |x| < 4
(2) y > 16


Kudos for correct solution.



1) No info about Y......Insuf

2) No info about X......Insuf


Combine 1&2

X=2 Y= 17.....XY=34>16

X=-2 Y=17.....XY=-34<16

Answer: E
Manager
Manager
avatar
G
Joined: 12 Jun 2016
Posts: 218
Location: India
Concentration: Technology, Leadership
WE: Sales (Telecommunications)
GMAT ToolKit User
Is xy > 16?  [#permalink]

Show Tags

New post Updated on: 20 Sep 2017, 21:35
Here's My solution

Stem: Is XY > 16. (Note: No constraints given. Both X and y could be positive, Negative, Zero, Integer, Non integer)

S1: 1 < |x| < 4
Tells us X = any number on the number line between 1 and 4 or any number on number line between -1 and -4. Also no information on Y.
Insuff

S2: Y > 16
Tells us Y could be anything from 16 to Infinity. However no info on X. If X = 0 or negative XY is less then 16 and if X is 1, XY = 16 and if X is positive and greater then 1 XY is greater then 16.
Insuff

S1+S2: X is any number on the number line between 1 and 4 or -1 and -4. Y is greater then 16. XY is less then 16 is X is negative. Its more then 16 if x is positive.
Insuff

Final Answer : E

Bunuel wrote:
Is xy > 16?

(1) 1 < |x| < 4
(2) y > 16


Kudos for correct solution.

_________________

My Best is yet to come!


Originally posted by susheelh on 29 Jun 2017, 10:40.
Last edited by susheelh on 20 Sep 2017, 21:35, edited 1 time in total.
Retired Moderator
User avatar
P
Joined: 19 Mar 2014
Posts: 962
Location: India
Concentration: Finance, Entrepreneurship
GPA: 3.5
GMAT ToolKit User Premium Member
Re: Is xy > 16?  [#permalink]

Show Tags

New post 29 Jun 2017, 14:22
Is \(xy > 16\)?

\((1) 1 < |x| < 4\)

This equation does not tell us anything about \(y\) and \(y\) can take any possible value.

Hence, (1) =====> is NOT SUFFICIENT

\((2) y > 16\)

This equation does not tell us anything about \(x\) and \(x\) can take any possible value.

Hence, (2) =====> is NOT SUFFICIENT

Combining (1) & (2)

We know y > 16

And, x can be -3, -2 or 3 & 2

As x can take both positive and negative values, the we will get answer to the question \(xy > 16\) as TRUE and FALSE

Hence, Combined (1) & (2) =====> is NOT SUFFICIENT

Hence, Answer is E
_________________

"Nothing in this world can take the place of persistence. Talent will not: nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not: the world is full of educated derelicts. Persistence and determination alone are omnipotent."

Best AWA Template: https://gmatclub.com/forum/how-to-get-6-0-awa-my-guide-64327.html#p470475

Manager
Manager
User avatar
G
Joined: 22 Nov 2016
Posts: 228
Location: United States
Concentration: Leadership, Strategy
GPA: 3.4
Reviews Badge
Is xy > 16?  [#permalink]

Show Tags

New post 20 Sep 2017, 15:07
Statement 1) 1 < |x| < 4

No information about Y. Insufficient. AD BCE

Statement 2) Y > 16

No information about X. Insufficient. B CE

Using 1 and 2.

X = -1 and Y=20; Thus XY < 16
or
X = 2 and Y=20; XY = 40; Thus XY > 16

Answer is E
_________________

Kudosity killed the cat but your kudos can save it.

VP
VP
User avatar
V
Status: It's near - I can see.
Joined: 13 Apr 2013
Posts: 1256
Location: India
Concentration: International Business, Operations
GMAT 1: 480 Q38 V22
GPA: 3.01
WE: Engineering (Consulting)
Premium Member Reviews Badge CAT Tests
Re: Is xy > 16?  [#permalink]

Show Tags

New post 09 Mar 2018, 03:29
Bunuel wrote:
Is xy > 16?

(1) 1 < |x| < 4
(2) y > 16


Kudos for correct solution.


I got it wrong.

Question: Is xy > 16?

To get this, we need to prove that both x and y have the same sign.

St 1: 1 < |x| < 4

means x can be in between 1 & 4 or -1 & -4

Also we don't know what "y" is? Not Sufficient

St 2: y > 16

As we don't know anything about "x", it is Not Sufficient

Combining St 1 & 2 we don't whether xy > 16

If x is in between 1& 4, answer is YES

If x is in between -1 & -4, answer is NO.

(E)
_________________

"Do not watch clock; Do what it does. KEEP GOING."

CEO
CEO
User avatar
D
Joined: 12 Sep 2015
Posts: 2845
Location: Canada
Re: Is xy > 16?  [#permalink]

Show Tags

New post 09 Mar 2018, 08:22
Top Contributor
Bunuel wrote:
Is xy > 16?

(1) 1 < |x| < 4
(2) y > 16


Target question: Is xy > 16?

Statement 1: 1 < |x| < 4
Since there's no information about y, we cannot determine whether xy is greater than 16
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: y > 16
Since there's no information about x, we cannot determine whether xy is greater than 16
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
There are several values of x and y that satisfy BOTH statements. Here are two:
Case a: x = 2 and y = 20, in which case xy = 40. In this case, the answer to the target question is YES, xy IS greater than 16
Case b: x = -2 and y = 20, in which case xy = -40. In this case, the answer to the target question is NO, xy is NOT greater than 16
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer: E

Cheers,
Brent
_________________

Brent Hanneson – GMATPrepNow.com
Image
Sign up for our free Question of the Day emails

Re: Is xy > 16? &nbs [#permalink] 09 Mar 2018, 08:22
Display posts from previous: Sort by

Is xy > 16?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  

Events & Promotions

PREV
NEXT


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.