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

It is currently 17 Jun 2018, 21:05

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

If r is a prime number and s is a positive integer, is

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

Hide Tags

1 KUDOS received
Current Student
avatar
Joined: 29 Apr 2015
Posts: 26
Location: Russian Federation
GMAT 1: 710 Q48 V38
GPA: 4
GMAT ToolKit User
If r is a prime number and s is a positive integer, is [#permalink]

Show Tags

New post Updated on: 20 Jan 2016, 04:52
1
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

34% (00:49) correct 66% (00:51) wrong based on 50 sessions

HideShow timer Statistics

If r is a prime number and s is a positive integer, is \(\frac{r^3}{s}\) a terminating decimal?


(1) r \(\geq\) 5
(2) s = 75

Originally posted by naumyuk on 20 Jan 2016, 00:15.
Last edited by naumyuk on 20 Jan 2016, 04:52, edited 1 time in total.
Expert Post
2 KUDOS received
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 5875
Re: If r is a prime number and s is a positive integer, is [#permalink]

Show Tags

New post 20 Jan 2016, 01:04
2
1
naumyuk wrote:
If r is a prime number and s is a positive integer, is a \(\frac{r^3}{c}\) terminating decimal?


(1) r \(\geq\) 5
(2) s = 75


Editing your Q as in present state answer is E..
c in \(\frac{r^3}{c}\) must be 's'..

so we have to find if \(\frac{r^3}{s}\) is a terminating decimal...
the value depends on the denominator in its simplified form..

lets see the statements..

(1) r \(\geq\) 5
it just tell us that r cannot br 2 and 3 nothing else..
insuff

(2) s = 75
the denominator is 75...
if the numerator is 3 it will be a terminating decimal, otherwise not...
insuff..

combined we know numerator does not have 3, so it will not be a terminating decimal, as we have 3 in denominator..
suff
C
_________________

Absolute modulus :http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html


GMAT online Tutor

Manager
Manager
avatar
S
Joined: 19 Aug 2016
Posts: 153
Location: India
GMAT 1: 640 Q47 V31
GPA: 3.82
Reviews Badge
Re: If r is a prime number and s is a positive integer, is [#permalink]

Show Tags

New post 10 Apr 2017, 04:58
chetan2u wrote:
naumyuk wrote:
If r is a prime number and s is a positive integer, is a \(\frac{r^3}{c}\) terminating decimal?


(1) r \(\geq\) 5
(2) s = 75


Editing your Q as in present state answer is E..
c in \(\frac{r^3}{c}\) must be 's'..

so we have to find if \(\frac{r^3}{s}\) is a terminating decimal...
the value depends on the denominator in its simplified form..

lets see the statements..

(1) r \(\geq\) 5
it just tell us that r cannot br 2 and 3 nothing else..
insuff

(2) s = 75
the denominator is 75...
if the numerator is 3 it will be a terminating decimal, otherwise not...
insuff..

combined we know numerator does not have 3, so it will not be a terminating decimal, as we have 3 in denominator..
suff
C



I am sorry I am slightly confused with the explanation. As far as my understanding goes, if the denominator has any other prime number in prime factorisation other than 2 and 5 and if that prime number can be cancelled with the numerator, then the fraction is terminating, otherwise not.

Here, the numerator is >or = to 5 i.e. it could also be 6 or 9 or 12 and those cases the 3 in the denominator will get cancelled. Therefore, there is no way to know what the value of r could be. Hence, my answer was E.

Kindly explain.
_________________

Consider giving me Kudos if you find my posts useful, challenging and helpful!

SVP
SVP
User avatar
P
Joined: 26 Mar 2013
Posts: 1671
Reviews Badge CAT Tests
Re: If r is a prime number and s is a positive integer, is [#permalink]

Show Tags

New post 10 Apr 2017, 05:07
ashikaverma13 wrote:


I am sorry I am slightly confused with the explanation. As far as my understanding goes, if the denominator has any other prime number in prime factorisation other than 2 and 5 and if that prime number can be cancelled with the numerator, then the fraction is terminating, otherwise not.

Here, the numerator is >or = to 5 i.e. it could also be 6 or 9 or 12 and those cases the 3 in the denominator will get cancelled. Therefore, there is no way to know what the value of r could be. Hence, my answer was E.

Kindly explain.



The prompt says that r is PRIME number. So it can't be 6 or 9 or 12.
Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 46047
Re: If r is a prime number and s is a positive integer, is [#permalink]

Show Tags

New post 10 Apr 2017, 05:10
ashikaverma13 wrote:
chetan2u wrote:
naumyuk wrote:
If r is a prime number and s is a positive integer, is a \(\frac{r^3}{c}\) terminating decimal?


(1) r \(\geq\) 5
(2) s = 75


Editing your Q as in present state answer is E..
c in \(\frac{r^3}{c}\) must be 's'..

so we have to find if \(\frac{r^3}{s}\) is a terminating decimal...
the value depends on the denominator in its simplified form..

lets see the statements..

(1) r \(\geq\) 5
it just tell us that r cannot br 2 and 3 nothing else..
insuff

(2) s = 75
the denominator is 75...
if the numerator is 3 it will be a terminating decimal, otherwise not...
insuff..

combined we know numerator does not have 3, so it will not be a terminating decimal, as we have 3 in denominator..
suff
C



I am sorry I am slightly confused with the explanation. As far as my understanding goes, if the denominator has any other prime number in prime factorisation other than 2 and 5 and if that prime number can be cancelled with the numerator, then the fraction is terminating, otherwise not.

Here, the numerator is >or = to 5 i.e. it could also be 6 or 9 or 12 and those cases the 3 in the denominator will get cancelled. Therefore, there is no way to know what the value of r could be. Hence, my answer was E.

Kindly explain.


Notice that we are told that r is a prime number, so it cannot be any multiple of 3 apart from 3 itself but r = 3 is ruled out with the first statement.
_________________

New to the Math Forum?
Please read this: Ultimate GMAT Quantitative Megathread | All You Need for Quant | PLEASE READ AND FOLLOW: 12 Rules for Posting!!!

Resources:
GMAT Math Book | Triangles | Polygons | Coordinate Geometry | Factorials | Circles | Number Theory | Remainders; 8. Overlapping Sets | PDF of Math Book; 10. Remainders | GMAT Prep Software Analysis | SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) | Tricky questions from previous years.

Collection of Questions:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
Extra-hard Quant Tests with Brilliant Analytics

Re: If r is a prime number and s is a positive integer, is   [#permalink] 10 Apr 2017, 05:10
Display posts from previous: Sort by

If r is a prime number and s is a positive integer, is

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


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®.