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

It is currently 23 Jul 2014, 01:55

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 P, Q, R, and S are positive integers, and P/Q = R/S, is R

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
avatar
Joined: 29 Aug 2005
Posts: 283
Followers: 1

Kudos [?]: 21 [0], given: 0

GMAT Tests User
If P, Q, R, and S are positive integers, and P/Q = R/S, is R [#permalink] New post 02 Jul 2008, 21:20
2
This post was
BOOKMARKED
If P, Q, R, and S are positive integers, and P/Q = R/S, is R divisible by 5 ?

(1) P is divisible by 140

(2)Q = 7^x , where x is a positive integer

Source :- http://blog.clearadmit.com/

we will have to wait for the OA for this for one week

let us discuss it

here is my attempt at the problem

IMO A is the answer to this one

my line of reasoning is as follows

statement 1 tells us that P is divisible by 140 and the stem tell us that P,Q,R,S are positive numbers
so it means that P will be a multiple of 140 at each time

now let us try picking and plugging some numbers in the equation as per the stem
let us say p = 280 Q = 3. now since P/Q equals R/S therefore we know that R/S will always represent 280/3 . which means that R will always be a multiple of 5

statement 2, we only know that Q=7^x and x is any positive number, but we do not know about what are the other numbers viz, P,R,S. therefore this statement alone is insufficent

Accordingly, A is the answer for this

I hope i have taken the correct approach to solve the question and arrived at the correct answer

Comments please

Many thanks

_________________

The world is continuous, but the mind is discrete

Director
Director
avatar
Joined: 27 May 2008
Posts: 552
Followers: 5

Kudos [?]: 161 [0], given: 0

GMAT Tests User
Re: Manhattan workbook wednesday question [#permalink] New post 02 Jul 2008, 21:33
P/Q = R/S
PS = QR

Statement 1 : P = 140y

140y * S = Q * R

we can have y = 1, S = 1, Q = 14, R = 10, divisible by 5
OR we can have y=1, S=1, Q=10, R=14, not divisible by 5

Not Suff

Statement 2 : Q = 7x, R can take any vaue... Not suff

Combine 140y * S = 7x * R
R = 20y * S / x

if x = 20, y = 1, S = anything ..... we can not determine R's divisibility with 5

IMO E.
Senior Manager
Senior Manager
avatar
Joined: 29 Aug 2005
Posts: 283
Followers: 1

Kudos [?]: 21 [0], given: 0

GMAT Tests User
Re: Manhattan workbook wednesday question [#permalink] New post 02 Jul 2008, 21:41
rohit929 wrote:
vdhawan1 wrote:
If P, Q, R, and S are positive integers, and P/Q = R/S, is R divisible by 5 ?

(1) P is divisible by 140

(2)Q = 7^x , where x is a positive integer

Source :- http://blog.clearadmit.com/

we will have to wait for the OA for this for one week

let us discuss it

here is my attempt at the problem

IMO A is the answer to this one

my line of reasoning is as follows

statement 1 tells us that P is divisible by 140 and the stem tell us that P,Q,R,S are positive numbers
so it means that P will be a multiple of 140 at each time

now let us try picking and plugging some numbers in the equation as per the stem
let us say p = 280 Q = 3. now since P/Q equals R/S therefore we know that R/S will always represent 280/3 . which means that R will always be a multiple of 5

statement 2, we only know that Q=7^x and x is any positive number, but we do not know about what are the other numbers viz, P,R,S. therefore this statement alone is insufficent

Accordingly, A is the answer for this

I hope i have taken the correct approach to solve the question and arrived at the correct answer

P/Q = R/S
PS=RQ
(1) P is divisible by 140
140 k*s=RQ

now if k=2 and Q=140 and s=1 then r is not divisible by 5
Insuff

(2)Q = 7^x , where x is a positive integer

Insuff

combine
140 k*s=R 7^x

R=(140 k*s/(7^x))

since R is an integer and (7^x) can never be a multiple of 10 ,R is divisible by 5


Comments please

Many thanks


Ok i see i mistake in statement 1 (thanks for pointing this out)
but i just have one question

u say that

Quote:
140 k*s=R 7^x

R=(140 k*s/(7^x))

since R is an integer and (7^x) can never be a multiple of 10 ,R is divisible by 5


agreed that (7^x) can never be a multiple of 10, but let us try some numbers then let us say x =2 and k and s = 1
what we get is R=140/49 which then clearly is not divisible by 5

so then the answer to this should be E

what do u think

_________________

The world is continuous, but the mind is discrete

Manager
Manager
avatar
Joined: 10 Mar 2008
Posts: 67
Followers: 2

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

Re: Manhattan workbook wednesday question [#permalink] New post 02 Jul 2008, 21:53
vdhawan1 wrote:
rohit929 wrote:
vdhawan1 wrote:
If P, Q, R, and S are positive integers, and P/Q = R/S, is R divisible by 5 ?

(1) P is divisible by 140

(2)Q = 7^x , where x is a positive integer

Source :- http://blog.clearadmit.com/

we will have to wait for the OA for this for one week

let us discuss it

here is my attempt at the problem

IMO A is the answer to this one

my line of reasoning is as follows

statement 1 tells us that P is divisible by 140 and the stem tell us that P,Q,R,S are positive numbers
so it means that P will be a multiple of 140 at each time

now let us try picking and plugging some numbers in the equation as per the stem
let us say p = 280 Q = 3. now since P/Q equals R/S therefore we know that R/S will always represent 280/3 . which means that R will always be a multiple of 5

statement 2, we only know that Q=7^x and x is any positive number, but we do not know about what are the other numbers viz, P,R,S. therefore this statement alone is insufficent

Accordingly, A is the answer for this

I hope i have taken the correct approach to solve the question and arrived at the correct answer

P/Q = R/S
PS=RQ
(1) P is divisible by 140
140 k*s=RQ

now if k=2 and Q=140 and s=1 then r is not divisible by 5
Insuff

(2)Q = 7^x , where x is a positive integer

Insuff

combine
140 k*s=R 7^x

R=(140 k*s/(7^x))

since R is an integer and (7^x) can never be a multiple of 10 ,R is divisible by 5


Comments please

Many thanks


Ok i see i mistake in statement 1 (thanks for pointing this out)
but i just have one question

u say that

Quote:
140 k*s=R 7^x

R=(140 k*s/(7^x))

since R is an integer and (7^x) can never be a multiple of 10 ,R is divisible by 5


agreed that (7^x) can never be a multiple of 10, but let us try some numbers then let us say x =2 and k and s = 1
what we get is R=140/49 which then clearly is not divisible by 5

so then the answer to this should be E

what do u think


why are you people forgetting
If P, Q, R, and S are positive integers

so R=140/49 is not possible
Director
Director
avatar
Joined: 27 May 2008
Posts: 552
Followers: 5

Kudos [?]: 161 [0], given: 0

GMAT Tests User
Re: Manhattan workbook wednesday question [#permalink] New post 02 Jul 2008, 21:57
thanks for pointing out my mistake. 7^x and 7*x.

The answer should be C, because as per question stem, R has to be an interger.
Senior Manager
Senior Manager
avatar
Joined: 29 Aug 2005
Posts: 283
Followers: 1

Kudos [?]: 21 [0], given: 0

GMAT Tests User
Re: Manhattan workbook wednesday question [#permalink] New post 03 Jul 2008, 02:56
If P, Q, R, and S are positive integers, and P/Q = R/S, is R divisible by 5 ?

(1) P is divisible by 140

(2)Q = 7^x , where x is a positive integer

Source :- http://blog.clearadmit.com/

we will have to wait for the OA for this for one week

let us discuss it

here is my attempt at the problem

IMO A is the answer to this one

my line of reasoning is as follows

statement 1 tells us that P is divisible by 140 and the stem tell us that P,Q,R,S are positive numbers
so it means that P will be a multiple of 140 at each time

now let us try picking and plugging some numbers in the equation as per the stem
let us say p = 280 Q = 3. now since P/Q equals R/S therefore we know that R/S will always represent 280/3 . which means that R will always be a multiple of 5

statement 2, we only know that Q=7^x and x is any positive number, but we do not know about what are the other numbers viz, P,R,S. therefore this statement alone is insufficent

Accordingly, A is the answer for this

I hope i have taken the correct approach to solve the question and arrived at the correct answer

P/Q = R/S
PS=RQ
(1) P is divisible by 140
140 k*s=RQ

now if k=2 and Q=140 and s=1 then r is not divisible by 5
Insuff

(2)Q = 7^x , where x is a positive integer

Insuff

combine
140 k*s=R 7^x

R=(140 k*s/(7^x))

since R is an integer and (7^x) can never be a multiple of 10 ,R is divisible by 5


Comments please

Many thanks[/quote][/quote]

Ok i see i mistake in statement 1 (thanks for pointing this out)
but i just have one question

u say that

Quote:
140 k*s=R 7^x

R=(140 k*s/(7^x))

since R is an integer and (7^x) can never be a multiple of 10 ,R is divisible by 5


agreed that (7^x) can never be a multiple of 10, but let us try some numbers then let us say x =2 and k and s = 1
what we get is R=140/49 which then clearly is not divisible by 5

so then the answer to this should be E

what do u think[/quote]

why are you people forgetting
If P, Q, R, and S are positive integers

so R=140/49 is not possible[/quote]


Ok got it

thanks for pointing this out

wonder where my attention was

_________________

The world is continuous, but the mind is discrete

Senior Manager
Senior Manager
User avatar
Joined: 21 Apr 2008
Posts: 497
Schools: Kellogg, MIT, Michigan, Berkeley, Marshall, Mellon
Followers: 6

Kudos [?]: 24 [0], given: 13

GMAT Tests User
Re: Manhattan workbook wednesday question [#permalink] New post 03 Jul 2008, 03:28
I get answer C too, following the same reasoning as vdhawan1 did

Please, post the official solution

Regards

_________________

mates, please visit my profile and leave comments
johnlewis1980-s-profile-feedback-is-more-than-welcome-80538.html

I'm not linked to GMAT questions anymore, so, if you need something, please PM me

I'm already focused on my application package :)

My experience in my second attempt
http://gmatclub.com/forum/p544312#p544312
My experience in my third attempt
630-q-47-v-28-engineer-non-native-speaker-my-experience-78215.html#p588275

SVP
SVP
User avatar
Joined: 30 Apr 2008
Posts: 1893
Location: Oklahoma City
Schools: Hard Knocks
Followers: 28

Kudos [?]: 423 [0], given: 32

GMAT Tests User
Re: Manhattan workbook wednesday question [#permalink] New post 03 Jul 2008, 05:26
I think the answer should be E.

vdhawan1 wrote:
If P, Q, R, and S are positive integers, and P/Q = R/S, is R divisible by 5 ?

(1) P is divisible by 140

(2)Q = 7^x , where x is a positive integer


Statement 1) First, all we know is P is divisible by 140, we don't know at all what Q is. The value of Q will help determine what value R can be.

If p = 140 (which is divisible by 140), we must pick a number for Q. We could pick 280 for Q, and so 140 / 280 = 1/2. R could be 1 and that is not divisible by 5. The question asked of us is essentially "Is R always or never divisible by 5?" If we can come to a conclusion of "always" or "never" - the statement is sufficient. Becuase we can't do that for #1, it is insufficient.

Statement 2) This fails for a similar reason to Statement 1. We know possible values of Q, but we don't know the value of P. If x = 2, then Q = 49 (7^2=49). We are not limited at all as to what q can be. Insufficient.

Together) This should prove to be sufficient. If P is a multiple of 140, and Q is 7^x, we need to see what values are available for R/S.

Factors of 140 will help us determine if (when reduced) the value will be divisible by 5.

1-2-4-5-10-14-28-35-70-140.

Some available numbers for Q:
7-49-343-2401...(I stopped doing the math, because there is a useful principle here).

The only factors of (7^x) will be the number itself and the numbers ahead of it in the progression of 7^x (i.e., factors of 7^5 = 7^1, 7^2, 7^3, 7^4,7^5) There is a pattern that emerges here with the units column (the column that tells us if it is divisible by 5).

The units are
7^1 = 7
7^2 = 9
7^3 = 3
7^4 = 1
7^5 = 7
7^6 = 9
7^7 = 3
7^8 = 1
7^9 = 7
7^10 = 9
7^11 = 3

You see the pattern. So no matter what P/Q is, it will never be reduced down to something that makes P divisible by 5. Any multiple of 140 divided by 7^x will not leave a 5 or 0 in the units column because any multiple of 140 will have a 0 in the units column and in order to divide anything with a 0 in the units column and result in a 0 or 5 in the units column you mus divide by multiples of 5 or 10 (and mulltiples of 2 [that are also not multiples of 6]).

After all of this analysis and I was ready to write the answer is C, the thought struck me.

If P/Q = R/S, and P=140 and Q = 7^x, P/Q could be 140/49. and if that = RS, there is nothing that would keep R/S from being 140/49 and R is then divisible by 5. The reasoning above shows that we can find plenty of situations that R is not divisible by 5, but because we found one where R is divisible by 5

Answer has to be E.

_________________

------------------------------------
J Allen Morris
**I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a$$.

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Director
Director
avatar
Joined: 01 Jan 2008
Posts: 629
Followers: 3

Kudos [?]: 128 [0], given: 1

GMAT Tests User
Re: Manhattan workbook wednesday question [#permalink] New post 03 Jul 2008, 06:01
P/Q = R/S

R = (P/Q)*S

1) P = 140*k -> obviously insufficient (P=140,Q=70, S=1,R=2), (P=140, Q=70, S = 5, R = 10)
2) Q = 7^x -> insufficient

1&2: R = (P/Q)*S = (7*20*k/7^x)*S = 20*(k/7^(x-1))*S -> divisible by 5, sufficient -> C
SVP
SVP
User avatar
Joined: 30 Apr 2008
Posts: 1893
Location: Oklahoma City
Schools: Hard Knocks
Followers: 28

Kudos [?]: 423 [0], given: 32

GMAT Tests User
Re: Manhattan workbook wednesday question [#permalink] New post 03 Jul 2008, 06:01
The answer is up there and the answer is C. It's a good explanation.

http://blog.clearadmit.com/

_________________

------------------------------------
J Allen Morris
**I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a$$.

Get the best GMAT Prep Resources with GMAT Club Premium Membership

CEO
CEO
User avatar
Joined: 29 Mar 2007
Posts: 2593
Followers: 16

Kudos [?]: 179 [0], given: 0

GMAT Tests User
Re: Manhattan workbook wednesday question [#permalink] New post 03 Jul 2008, 06:40
vdhawan1 wrote:
If P, Q, R, and S are positive integers, and P/Q = R/S, is R divisible by 5 ?

(1) P is divisible by 140

(2)Q = 7^x , where x is a positive integer

Source :- http://blog.clearadmit.com/

we will have to wait for the OA for this for one week

let us discuss it

here is my attempt at the problem

IMO A is the answer to this one

my line of reasoning is as follows

statement 1 tells us that P is divisible by 140 and the stem tell us that P,Q,R,S are positive numbers
so it means that P will be a multiple of 140 at each time

now let us try picking and plugging some numbers in the equation as per the stem
let us say p = 280 Q = 3. now since P/Q equals R/S therefore we know that R/S will always represent 280/3 . which means that R will always be a multiple of 5

statement 2, we only know that Q=7^x and x is any positive number, but we do not know about what are the other numbers viz, P,R,S. therefore this statement alone is insufficent

Accordingly, A is the answer for this

I hope i have taken the correct approach to solve the question and arrived at the correct answer

Comments please

Many thanks



S1: Insuff. Try 140/10 = 140/10 or 140/10 = 28/2

S2: Insuff. Tells us nothing.

Together:

Suff.
Re: Manhattan workbook wednesday question   [#permalink] 03 Jul 2008, 06:40
    Similar topics Author Replies Last post
Similar
Topics:
2 Experts publish their posts in the topic If p, q, and r are integers, is pq + r even? karmapatell 3 07 Apr 2013, 02:26
1 Experts publish their posts in the topic If P, Q, R, and S are positive integers, and P/Q = R/S, is R rxs0005 8 01 Feb 2011, 10:01
Is p+q > r+s? A. p > r+s B. q > r+s zaarathelab 3 11 Nov 2009, 08:24
Is p+q > r+s? ggarr 4 14 Dec 2006, 17:53
Is p+q > r+s? 1) p> r+s 2) q > r+s ggarr 2 14 Dec 2006, 17:44
Display posts from previous: Sort by

If P, Q, R, and S are positive integers, and P/Q = R/S, is R

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Privacy Policy| 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®.