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

 It is currently 17 Dec 2018, 00:19

### 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 December
PrevNext
SuMoTuWeThFrSa
2526272829301
2345678
9101112131415
16171819202122
23242526272829
303112345
Open Detailed Calendar
• ### 10 Keys to nail DS and CR questions

December 17, 2018

December 17, 2018

06:00 PM PST

07:00 PM PST

Join our live webinar and learn how to approach Data Sufficiency and Critical Reasoning problems, how to identify the best way to solve each question and what most people do wrong.
• ### R1 Admission Decisions: Estimated Decision Timelines and Chat Links for Major BSchools

December 17, 2018

December 17, 2018

10:00 PM PST

11:00 PM PST

From Dec 5th onward, American programs will start releasing R1 decisions. Chat Rooms: We have also assigned chat rooms for every school so that applicants can stay in touch and exchange information/update during decision period.

# If x and y are nonnegative integers, what is the value of y?

Author Message
TAGS:

### Hide Tags

Manager
Joined: 02 May 2012
Posts: 68
If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

Updated on: 05 Nov 2014, 03:44
7
00:00

Difficulty:

55% (hard)

Question Stats:

53% (01:13) correct 47% (01:33) wrong based on 261 sessions

### HideShow timer Statistics

If x and y are nonnegative integers, what is the value of y?

(1) 3^x = 5^y
(2) |y| = −y

_________________

If you like my post Kudos Please
__________________________________________________
Support ====> http://udaanshimla.ketto.org/campaign/campaign_details.php?fmd_id=757

Originally posted by aashu4uiit on 04 Nov 2014, 11:05.
Last edited by Bunuel on 05 Nov 2014, 03:44, edited 3 times in total.
Edited the question.
Math Expert
Joined: 02 Sep 2009
Posts: 51239
Re: If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

05 Nov 2014, 03:48
5
3
If x and y are nonnegative integers, what is the value of y?

(1) 3^x = 5^y. Since x and y are integers then x = y = 0. Sufficient.

(2) |y| = −y --> $$y\leq{0}$$. From the stem we know that $$y\geq{0}$$, therefore y = 0. Sufficient.

_________________
##### General Discussion
Intern
Joined: 23 Oct 2012
Posts: 44
Re: If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

04 Nov 2014, 12:36
1) x could be 0 or 3 as its a non negative number ( 0 or >0), so A is not sufficient.

2) this doesn't give us any specific value. Not sufficient.

1 + 2 -- No specific value.

_________________

Manager
Joined: 21 Jul 2014
Posts: 125
Re: If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

04 Nov 2014, 13:21
1
1
aashu4uiit wrote:
If x and y are nonnegative integers, what is the value of y?

(1) 3x = 5y
(2) |y| = −y

Can someone share how to solve this one , I got stuck with statement 2.

Please note, the original question changed since my post.

I disagree with the official answer. Here's why I think the answer is B (statement 2 alone is sufficient).

Statement 1:
3x = 5y

y has an infinite number of possibilities. For example...
x=0, y=0
x=5, y=3
x=10, y=6
x=15, y=9

Therefore, statement 1 is insufficient.

Eliminate answer choice A and D.

Statement 2:
|y| = -y

This statement requires an understanding of absolute value notation (that is what the vertical lines around y mean). Absolute value is by definition the magnitude of a number without regard to its sign. This means that the absolute value of any number cannot be negative, since negative is a sign, UNLESS you count absolute value of zero.

The only possible value of y in this case is y=0.

Eliminate C and E.

Manager
Joined: 12 Sep 2014
Posts: 145
GMAT 1: 740 Q49 V41
GPA: 3.94
Re: If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

04 Nov 2014, 13:29
Agree with lighthouse on this one... It's B.

A is not sufficient as there are many possibilities, but with B, y can only be zero.
Manager
Joined: 02 May 2012
Posts: 68
Re: If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

04 Nov 2014, 13:35
Just corrected the question .

It's D , My doubt about statement 2 is clear now.

Thanks
_________________

If you like my post Kudos Please
__________________________________________________
Support ====> http://udaanshimla.ketto.org/campaign/campaign_details.php?fmd_id=757

Intern
Joined: 26 May 2014
Posts: 7
Location: India
Re: If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

11 Nov 2014, 08:14
Hi Bunuel,

I am unable to understand how you stated -

(1) 3^x = 5^y. Since x and y are integers then x = y = 0. Sufficient.

As per my understanding x & y can have multiple value combinations.
Math Expert
Joined: 02 Sep 2009
Posts: 51239
Re: If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

11 Nov 2014, 08:24
1
2
Avisek47 wrote:
Hi Bunuel,

I am unable to understand how you stated -

(1) 3^x = 5^y. Since x and y are integers then x = y = 0. Sufficient.

As per my understanding x & y can have multiple value combinations.

The crucial point is that x and y are integers. 3^x cannot be a multiple of 5 and 5^y cannot be a multiple of 3. Thus for 3^x = 5^y to be true both x and y must be 0.
_________________
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Posts: 6653
GMAT 1: 760 Q51 V42
GPA: 3.82
Re: If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

21 Nov 2015, 09:32
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.

If x and y are nonnegative integers, what is the value of y?

(1) 3^x = 5^y
(2) |y| = −y

There are 2 variables (x,y) and 2 equations are given by the 2 conditions, giving a high chance (C) will be our answer.
If we look at conditions together, x=y=0, making the answer seem like (C), but this is a commonly made mistake;

For condition 1, x=y=0. This is sufficient.
For condition 2, y<=0, this is non-negative so y=0. This is also sufficient.

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"

Retired Moderator
Joined: 19 Mar 2014
Posts: 941
Location: India
Concentration: Finance, Entrepreneurship
GPA: 3.5
Re: If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

25 Jun 2017, 12:53
x and y are non-negative integers - This means x & Y can be ZERO and Any POSITIVE integers.

y = ?

$$(1) 3^x = 5^y$$

As we can see that there is no value for x & y except ZERO which can satisfy this equation. So, we can write:

$$3^0 = 5^0$$

$$0 = 0$$

Or, we can write: $$x + y = 0$$ or $$x & y$$ are $$Zero$$, Hence, we know $$y = 0$$ =====> Hence, Eq. (1) =====> SUFFICIENT

$$(2) |y| = −y$$

Considering y is non-negative integer, the only integer which can satisfy this equation is $$y = 0$$

Hence, Eq. (2) =====> SUFFICIENT

You Liked the Answer? One Kudos Plz!
_________________

"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

Non-Human User
Joined: 09 Sep 2013
Posts: 9195
Re: If x and y are nonnegative integers, what is the value of y?  [#permalink]

### Show Tags

16 Aug 2018, 11:30
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Re: If x and y are nonnegative integers, what is the value of y? &nbs [#permalink] 16 Aug 2018, 11:30
Display posts from previous: Sort by