It is currently 22 Feb 2018, 00:33

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 a, b, x, and y are all positive, is a/b > x/y ?

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

Hide Tags

Expert Post
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 43862
If a, b, x, and y are all positive, is a/b > x/y ? [#permalink]

Show Tags

New post 24 Apr 2017, 02:34
Expert's post
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

76% (00:53) correct 24% (01:20) wrong based on 45 sessions

HideShow timer Statistics

1 KUDOS received
Senior Manager
Senior Manager
User avatar
G
Joined: 22 Jun 2016
Posts: 250
Reviews Badge
If a, b, x, and y are all positive, is a/b > x/y ? [#permalink]

Show Tags

New post 24 Apr 2017, 03:20
1
This post received
KUDOS
As a,b,x and y are positive, it makes our life easy while playing with inequalities.

we have to find is : a/b>x/y ---> ay>bx ---> ay-bx > 0

S1.
ay+1>bx ---> ay-bx>-1

So, we cannot say whether ay-bx is always > 0 (for ex. ay-bx could be -0.5)

Insufficient!


S2.

(ay/bx)^2 > (ay/bx) ---> ay/bx > 1 ---> ay>bx ---> ay-bx>0

Sufficient.

Hence, answer should be B.
_________________

P.S. Don't forget to give Kudos :)

Intern
Intern
avatar
B
Joined: 18 Jul 2016
Posts: 16
Re: If a, b, x, and y are all positive, is a/b > x/y ? [#permalink]

Show Tags

New post 24 Apr 2017, 03:23
rewrite the question as (ay/bx)>1

statement 1
> divide the entire inequality by bx
we get
(ay/bx) + (1/bx) > 1
that is (positive number) + (positive Number) >1. This does not say anything about (ay/bx) as it can be 0.5 or 1.5 and so on

This is not sufficient as we need to know whether (ay/bx)>1

Statement 2
(ay/bx)^2 > (ay/bx)
>(ay/bx)^2 - (ay/bx)>0
>(ay/bx)*((ay/bx)-1)>0

this means that either both the boldface terms are greater than zero or both are less than zero.
as a,y,b and x are positive (ay/bx) cannot be less than zero. Hence both cannot be less than zero.
Now both are greater than zero. which means,
(ay/bx)> 0 and (ay/bx) - 1 > 0

Remember that this is an AND condition. Both have to be true.

therefore ay/bx >1
statement 2 alone is sufficient.
So answer should be B
_________________

Engineer, Quant score 53 First attempt.

Director
Director
avatar
S
Joined: 21 Mar 2016
Posts: 551
Reviews Badge
Re: If a, b, x, and y are all positive, is a/b > x/y ? [#permalink]

Show Tags

New post 24 Apr 2017, 03:37
simplify the given stem

ay>bx
ay-bx >0 ????
stat 1: ay-bx > -1,,not suff

stat 2 : divide the entire equation by ax/by

gives ax/by >1

ax>by
ax-by >0.. suff

ans B
Senior Manager
Senior Manager
User avatar
G
Joined: 22 Jun 2016
Posts: 250
Reviews Badge
Re: If a, b, x, and y are all positive, is a/b > x/y ? [#permalink]

Show Tags

New post 24 Apr 2017, 03:37
skothaka wrote:
rewrite the question as (ay/bx)>1

statement 1
> divide the entire inequality by bx
we get
(ay/bx) + (1/bx) > 1
that is (positive number) + (positive Number) >1. This does not say anything about (ay/bx) as it can be 0.5 or 1.5 and so on

This is not sufficient as we need to know whether (ay/bx)>1

Statement 2
(ay/bx)^2 > (ay/bx)
>(ay/bx)^2 - (ay/bx)>0
>(ay/bx)*((ay/bx)-1)>0

this means that either both the boldface terms are greater than zero or both are less than zero.
as a,y,b and x are positive (ay/bx) cannot be less than zero. Hence both cannot be less than zero.
Now both are greater than zero. which means,
(ay/bx)> 0 and (ay/bx) - 1 > 0

Remember that this is an AND condition. Both have to be true.

therefore ay/bx >1
statement 2 alone is sufficient.
So answer should be B


The solution provided for S1 is not complete. We cannot conclude anything with the equation (ay/bx) + (1/bx) > 1. See the above solution for a better explanation.
_________________

P.S. Don't forget to give Kudos :)

Intern
Intern
avatar
B
Joined: 18 Jul 2016
Posts: 16
Re: If a, b, x, and y are all positive, is a/b > x/y ? [#permalink]

Show Tags

New post 24 Apr 2017, 03:42
14101992 wrote:
skothaka wrote:
rewrite the question as (ay/bx)>1

statement 1
> divide the entire inequality by bx
we get
(ay/bx) + (1/bx) > 1
that is (positive number) + (positive Number) >1. This does not say anything about (ay/bx) as it can be 0.5 or 1.5 and so on

This is not sufficient as we need to know whether (ay/bx)>1

Statement 2
(ay/bx)^2 > (ay/bx)
>(ay/bx)^2 - (ay/bx)>0
>(ay/bx)*((ay/bx)-1)>0

this means that either both the boldface terms are greater than zero or both are less than zero.
as a,y,b and x are positive (ay/bx) cannot be less than zero. Hence both cannot be less than zero.
Now both are greater than zero. which means,
(ay/bx)> 0 and (ay/bx) - 1 > 0

Remember that this is an AND condition. Both have to be true.

therefore ay/bx >1
statement 2 alone is sufficient.
So answer should be B


The solution provided for S1 is not complete. We cannot conclude anything with the equation (ay/bx) + (1/bx) > 1. See the above solution for a better explanation.



The solution for S1 says that ay/bx could be anything between 0 and infinite. So S1 is not sufficient. That is enough to rule it out. Your solution is much simpler btw.
_________________

Engineer, Quant score 53 First attempt.

Re: If a, b, x, and y are all positive, is a/b > x/y ?   [#permalink] 24 Apr 2017, 03:42
Display posts from previous: Sort by

If a, b, x, and y are all positive, is a/b > x/y ?

  new topic post reply 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 | 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®.