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

It is currently 13 Feb 2016, 16:37
GMAT Club Tests

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.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If px = qy, is x/y an integer?

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Expert Post
2 KUDOS received
Verbal Forum Moderator
Verbal Forum Moderator
User avatar
Joined: 10 Oct 2012
Posts: 630
Followers: 69

Kudos [?]: 877 [2] , given: 135

Top 10 in overall
If px = qy, is x/y an integer? [#permalink] New post 08 May 2013, 07:13
2
This post received
KUDOS
Expert's post
2
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

33% (01:55) correct 67% (01:01) wrong based on 88 sessions
If px = qy, is x/y an integer?

(1) q and p are primes.
(2) Positive integer y is neither composite nor prime

Question created by me.
[Reveal] Spoiler: OA

_________________

All that is equal and not-Deep Dive In-equality

Hit and Trial for Integral Solutions


Last edited by mau5 on 19 May 2013, 06:49, edited 1 time in total.
1 KUDOS received
VP
VP
User avatar
Status: Far, far away!
Joined: 02 Sep 2012
Posts: 1123
Location: Italy
Concentration: Finance, Entrepreneurship
GPA: 3.8
Followers: 163

Kudos [?]: 1613 [1] , given: 219

GMAT ToolKit User
Re: If px = qy, is x/y an integer? [#permalink] New post 08 May 2013, 07:28
1
This post received
KUDOS
If px = qy, is x/y an integer?

I.q and p are primes.
\(3*20=2*30\) => \(\frac{20}{30}\) no integer
\(3*1=3*1\) => \(\frac{1}{1}\) integer
Not sufficient

II. Positive integer y is neither composite nor prime
So y is \(1\), no info about x.
Not sufficient

I + II)\(px=q\), if \(p=q\) then \(x=1\) and \(\frac{x}{y}=\frac{1}{1}\) is an integer
if \(p\neq{q}\) ie: \(5*x=7, x=\frac{7}{5}\), then \(\frac{x}{y}\) is NOT an integer
Not sufficient.
E
_________________

It is beyond a doubt that all our knowledge that begins with experience.

Kant , Critique of Pure Reason

Tips and tricks: Inequalities , Mixture | Review: MGMAT workshop
Strategy: SmartGMAT v1.0 | Questions: Verbal challenge SC I-II- CR New SC set out !! , My Quant

Rules for Posting in the Verbal Forum - Rules for Posting in the Quant Forum[/size][/color][/b]

Expert Post
1 KUDOS received
Veritas Prep GMAT Instructor
User avatar
Joined: 16 Oct 2010
Posts: 6238
Location: Pune, India
Followers: 1683

Kudos [?]: 9660 [1] , given: 198

Re: If px = qy, is x/y an integer? [#permalink] New post 08 May 2013, 08:22
1
This post received
KUDOS
Expert's post
vinaymimani wrote:
If px = qy, is x/y an integer?

I.q and p are primes.
II. Positive integer y is neither composite nor prime


Question: is x/y an integer?

px = qy
x/y = q/p

We need to know whether q/p is an integer.

I.q and p are primes.
This means that q has only two factors - 1 and q itself. If p = q, then p is a factor q, else it is not.
Not sufficient.

II. Positive integer y is neither composite nor prime
This means y = 1. We still cannot say whether x/y is an integer since x may or may not be an integer.
Not sufficient.

Both taken together, nothing changes. We still do not know whether x/y is an integer.
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Get started with Veritas Prep GMAT On Demand for $199

Veritas Prep Reviews

GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 8238
Followers: 419

Kudos [?]: 111 [0], given: 0

Top 10 in overall
Re: If px = qy, is x/y an integer? [#permalink] New post 20 Dec 2015, 15:36
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.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Expert Post
Math Revolution GMAT Instructor
User avatar
Joined: 16 Aug 2015
Posts: 673
GPA: 3.82
Followers: 34

Kudos [?]: 258 [0], given: 0

Re: If px = qy, is x/y an integer? [#permalink] New post 21 Dec 2015, 21:47
Expert's post
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 px = qy, is x/y an integer?

(1) q and p are primes.
(2) Positive integer y is neither composite nor prime

In the original condition, there are 4 variables(pq,x,y) and 1 equations(px=qy), which should match with the number of equations. So you need 3 more equations. For 1) 1 equation, for 2) 1 equation, which is likely to make E the answer. In 1) & 2), from p=q=2, x/y=1, which is yes. From p=5, q=2, x=1, y=2.5, which is no. So it is not sufficient. Therefore, the answer is E.


-> For cases where we need 3 more equations, such as original conditions with “3 variables”, or “4 variables and 1 equation”, or “5 variables and 2 equations”, we have 1 equation each in both 1) and 2). Therefore, there is 80% chance that E is the answer (especially about 90% of 2 by 2 questions where there are more than 3 variables), while C has 15% 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 E 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, C or D.
_________________

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.
Find a 20% off coupon code for GMAT Club members.
Unlimited Access to over 120 free video lessons - try it yourself
See our Youtube demo

Re: If px = qy, is x/y an integer?   [#permalink] 21 Dec 2015, 21:47
    Similar topics Author Replies Last post
Similar
Topics:
3 Experts publish their posts in the topic Is xy an integer? Bunuel 5 23 Sep 2015, 01:46
3 Experts publish their posts in the topic If xy ≠ 0, is x an integer? Bunuel 8 11 Sep 2015, 01:05
4 Experts publish their posts in the topic Is xy an integer? Bunuel 5 30 Apr 2015, 03:06
5 Experts publish their posts in the topic If x is an integer, is (x + p)(x + q) an even integer? Bunuel 4 15 Dec 2014, 07:54
2 Experts publish their posts in the topic If x is an integer, is x/y an integer? DeeptiM 6 14 Aug 2011, 12:15
Display posts from previous: Sort by

If px = qy, is x/y an integer?

  Question banks Downloads My Bookmarks Reviews Important topics  


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

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®.