Last visit was: 11 Feb 2025, 13:27 It is currently 11 Feb 2025, 13:27
Decision Tracker
My Rewards
New comers' posts
New posts
Unanswered

Close

GRE Prep 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 GRE 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.

Go to My Error Log Learn more
Close

Request Expert Reply

Confirm Cancel
PREVIOUS TOPIC
NEXT TOPIC

If x - y = 9, which of the following would be sufficient to

Tags :
Find Similar Topics  About  Add a Tag

Show Tags
Hide Tags

User avatar
Farina
Senior Manager
Senior Manager
Joined: 10 Feb 2020
Posts: 496
Own Kudos [?]: 356 [1]
Given Kudos: 299
Send PM
If x - y = 9, which of the following would be sufficient to [#permalink] New post   19 Jul 2020, 23:09
1
Bookmarks
00:00

Question Stats:

41% (01:07) correct 58% (00:48) wrong based on 17 sessions

Hide Show timer Statistics

If \(x - y = 9\), which of the following would be sufficient to determine the values of both x and y individually?

Indicate all possible equations.

A. x + y = 13
B. x² - y² = 117
C. (x - y)² = 81
D. (x + y)² = 16
ShowHide Answer
Official Answer
A,B
avatar
sukrut96
Manager
Manager
Joined: 09 Mar 2020
Posts: 164
Own Kudos [?]: 202 [0]
Given Kudos: 0
Send PM
Re: If x - y = 9, which of the following would be sufficient to [#permalink] New post   19 Jul 2020, 23:20
Why not D ? We can take root such that x + y = 4 and then add the equations to get individual values of x and y. It is not specified that x and y are integer values.
User avatar
Farina
Senior Manager
Senior Manager
Joined: 10 Feb 2020
Posts: 496
Own Kudos [?]: 356 [0]
Given Kudos: 299
Send PM
Re: If x - y = 9, which of the following would be sufficient to [#permalink] New post   20 Jul 2020, 01:56
sukrut96 wrote:
Why not D ? We can take root such that x + y = 4 and then add the equations to get individual values of x and y. It is not specified that x and y are integer values.


It will be +4 and -4 I think..two roots I guess
avatar
sukrut96
Manager
Manager
Joined: 09 Mar 2020
Posts: 164
Own Kudos [?]: 202 [0]
Given Kudos: 0
Send PM
Re: If x - y = 9, which of the following would be sufficient to [#permalink] New post   20 Jul 2020, 02:22
Farina wrote:
sukrut96 wrote:
Why not D ? We can take root such that x + y = 4 and then add the equations to get individual values of x and y. It is not specified that x and y are integer values.


It will be +4 and -4 I think..two roots I guess


Yes, but still we can find out the values.
x - y = 9 and x + y = +-4
On adding the two equations, we get, x can be 6.5 or 2.5 (based on which value one chooses). And accordingly by substituting the value in first equation, we can find out y.
If the question mentioned that x and y are integers, then only A and B would satisfy the condition.
User avatar
Farina
Senior Manager
Senior Manager
Joined: 10 Feb 2020
Posts: 496
Own Kudos [?]: 356 [0]
Given Kudos: 299
Send PM
Re: If x - y = 9, which of the following would be sufficient to [#permalink] New post   20 Jul 2020, 02:42
sukrut96 wrote:
Farina wrote:
sukrut96 wrote:
Why not D ? We can take root such that x + y = 4 and then add the equations to get individual values of x and y. It is not specified that x and y are integer values.


It will be +4 and -4 I think..two roots I guess


Yes, but still we can find out the values.
x - y = 9 and x + y = +-4
On adding the two equations, we get, x can be 6.5 or 2.5 (based on which value one chooses). And accordingly by substituting the value in first equation, we can find out y.
If the question mentioned that x and y are integers, then only A and B would satisfy the condition.


Well acc. to the source the answers are A and B. I was also confused that is why posted the question here. Lets wait for the experts.
avatar
sukrut96
Manager
Manager
Joined: 09 Mar 2020
Posts: 164
Own Kudos [?]: 202 [0]
Given Kudos: 0
Send PM
Re: If x - y = 9, which of the following would be sufficient to [#permalink] New post   20 Jul 2020, 02:48
1
Okay sure :), can you please specify the source.
User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 30879
Own Kudos [?]: 37289 [0]
Given Kudos: 26161
Send PM
Re: If x - y = 9, which of the following would be sufficient to [#permalink] New post   20 Jul 2020, 05:33
Expert Reply
I disagree.

First, this is not a goo question and the wording is NOT from the GRE



however, pick up B for instance: it is \(x^2-y^2=117\)

\(x-y \times x+y=117\)


But x-y is 9 and x+y must be 13

However, x-y for being nine we could have a lot of values for x and y and the same for 13

which of the following would be sufficient to determine the values of both x and y individually?

I have some thought on this question
User avatar
Farina
Senior Manager
Senior Manager
Joined: 10 Feb 2020
Posts: 496
Own Kudos [?]: 356 [0]
Given Kudos: 299
Send PM
Re: If x - y = 9, which of the following would be sufficient to [#permalink] New post   20 Jul 2020, 05:50
Carcass wrote:
I disagree.

First, this is not a goo question and the wording is NOT from the GRE



however, pick up B for instance: it is \(x^2-y^2=117\)

\(x-y \times x+y=117\)


But x-y is 9 and x+y must be 13

However, x-y for being nine we could have a lot of values for x and y and the same for 13

which of the following would be sufficient to determine the values of both x and y individually?

I have some thought on this question


Carcass this question is from GRE tests of the greprepclub
User avatar
Farina
Senior Manager
Senior Manager
Joined: 10 Feb 2020
Posts: 496
Own Kudos [?]: 356 [0]
Given Kudos: 299
Send PM
Re: If x - y = 9, which of the following would be sufficient to [#permalink] New post   20 Jul 2020, 05:51
1
sukrut96 wrote:
Okay sure :), can you please specify the source.

greprepclub test
User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 30879
Own Kudos [?]: 37289 [0]
Given Kudos: 26161
Send PM
Re: If x - y = 9, which of the following would be sufficient to [#permalink] New post   20 Jul 2020, 07:54
Expert Reply
Mah.....

I am not the expert of the quant tests. For sure they know better than me :roll:
Prep Club for GRE Bot
gmatclubot
Re: If x - y = 9, which of the following would be sufficient to [#permalink]
20 Jul 2020, 07:54
Moderators:
adewale223
GRE Instructor
93 posts
bronaugust
GRE Forum Moderator
37 posts
BrushMyQuant
Moderator
1131 posts
VibhuAnurag
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Main navigation

Partners

GRE Resources

www.ets.org/gre | About | Terms and Conditions and Privacy Policy | Prep Club for GRE Rules | Contact