Last visit was: 04 Nov 2025, 16:02 It is currently 04 Nov 2025, 16:02
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

OA=AB

Tags :
Find Similar Topics  About  Add a Tag

Show Tags
Hide Tags

User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 33780
Own Kudos [?]: 40312 [3]
Given Kudos: 26600
Send PM
OA=AB [#permalink] New post   19 May 2021, 01:26
Expert Reply
3
Bookmarks
00:00

Question Stats:

56% (02:09) correct 43% (01:52) wrong based on 39 sessions

Hide Show timer Statistics

Attachment:
GRE OA=AB.jpg
GRE OA=AB.jpg [ 16.85 KiB | Viewed 4100 times ]


OA=AB


Quantity A
Quantity B
k
18



A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.

Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
ShowHide Answer
Official Answer
A
Most Helpful Community Reply
User avatar
D
KarunMendiratta
Retired Moderator
Joined: 16 Apr 2020
Status:Founder & Quant Trainer
Affiliations: Prepster Education
Posts: 1546
Own Kudos [?]: 3613 [3]
Given Kudos: 172
Location: India
WE:Education (Education)
Send PM
Re: OA=AB [#permalink] New post   19 May 2021, 12:32
3
Carcass wrote:
Attachment:
GRE OA=AB.jpg


OA=AB


Quantity A
Quantity B
k
18



A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.


OA = \(\sqrt{(18 - 0)^2 + (3 - 0)^2}\)

AB = \(\sqrt{(18 - 15)^2 + (3 - k)^2}\)

Since, OA = AB
\(\sqrt{(18 - 0)^2 + (3 - 0)^2} = \sqrt{(18 - 15)^2 + (3 - k)^2}\)

Squaring both sides;
\(18^2 + 3^2 = 3^2 + (3 - k)^2\)
\(18^2 = (3 - k)^2\)

On comparison;
either \((3 - k) = 18\) or \((3 - k) = -18\)

i.e. \(k = -15\) or \(21\)

Since, \(k\) is in Ist Quadrant \(k > 0\)

Hence, option A
General Discussion
avatar
MariaMughees
Intern
Intern
Joined: 08 Nov 2020
Posts: 3
Own Kudos [?]: 0 [0]
Given Kudos: 13
Send PM
Re: OA=AB [#permalink] New post   19 May 2021, 02:11
B

Posted from my mobile device
avatar
MariaMughees
Intern
Intern
Joined: 08 Nov 2020
Posts: 3
Own Kudos [?]: 0 [0]
Given Kudos: 13
Send PM
Re: OA=AB [#permalink] New post   19 May 2021, 02:14
K=21 so A

Posted from my mobile device
avatar
S
void
Senior Manager
Senior Manager
Joined: 03 Dec 2020
Posts: 440
Own Kudos [?]: 64 [0]
Given Kudos: 68
Send PM
Re: OA=AB [#permalink] New post   19 May 2021, 10:15
if you could not find out roots of equation then what to do??
avatar
S
COolguy101
Senior Manager
Senior Manager
Joined: 23 Jan 2021
Posts: 294
Own Kudos [?]: 184 [0]
Given Kudos: 81
Concentration: , International Business
Send PM
Re: OA=AB [#permalink] New post   01 Jun 2021, 19:53
KarunMendiratta wrote:
Carcass wrote:
Attachment:
GRE OA=AB.jpg


OA=AB


Quantity A
Quantity B
k
18



A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.


OA = \(\sqrt{(18 - 0)^2 + (3 - 0)^2}\)

AB = \(\sqrt{(18 - 15)^2 + (3 - k)^2}\)

Since, OA = AB
\(\sqrt{(18 - 0)^2 + (3 - 0)^2} = \sqrt{(18 - 15)^2 + (3 - k)^2}\)

Squaring both sides;
\(18^2 + 3^2 = 3^2 + (3 - k)^2\)
\(18^2 = (3 - k)^2\)

On comparison;
either \((3 - k) = 18\) or \((3 - k) = -18\)

i.e. \(k = -15\) or \(21\)

Since, \(k\) is in Ist Quadrant \(k > 0\)

Hence, option A


Cant we say that distance is always positive and neglect the negative value of K?
User avatar
D
rx10
Retired Moderator
Joined: 02 Dec 2020
Posts: 1831
Own Kudos [?]: 2162 [1]
Given Kudos: 140
GRE 1: Q168 V157

GRE 2: Q167 V161
Send PM
Re: OA=AB [#permalink] New post   02 Jun 2021, 02:37
1
Distance is always positive but what if point B was in 3rd quadrant? K will be -ve. but the distance will be +ve always.

Here B is in first quad hence -ve value is not considered.

Please ask if the doubt remains.

kumarneupane4344 wrote:
KarunMendiratta wrote:
Carcass wrote:
Attachment:
GRE OA=AB.jpg


OA=AB


Quantity A
Quantity B
k
18



A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.


OA = \(\sqrt{(18 - 0)^2 + (3 - 0)^2}\)

AB = \(\sqrt{(18 - 15)^2 + (3 - k)^2}\)

Since, OA = AB
\(\sqrt{(18 - 0)^2 + (3 - 0)^2} = \sqrt{(18 - 15)^2 + (3 - k)^2}\)

Squaring both sides;
\(18^2 + 3^2 = 3^2 + (3 - k)^2\)
\(18^2 = (3 - k)^2\)

On comparison;
either \((3 - k) = 18\) or \((3 - k) = -18\)

i.e. \(k = -15\) or \(21\)

Since, \(k\) is in Ist Quadrant \(k > 0\)

Hence, option A


Cant we say that distance is always positive and neglect the negative value of K?
avatar
S
void
Senior Manager
Senior Manager
Joined: 03 Dec 2020
Posts: 440
Own Kudos [?]: 64 [0]
Given Kudos: 68
Send PM
Re: OA=AB [#permalink] New post   03 Jun 2021, 08:05
hello expert, i am having little trouble with high difficulty level question, any suggestion!!!
User avatar
D
rx10
Retired Moderator
Joined: 02 Dec 2020
Posts: 1831
Own Kudos [?]: 2162 [0]
Given Kudos: 140
GRE 1: Q168 V157

GRE 2: Q167 V161
Send PM
Re: OA=AB [#permalink] New post   03 Jun 2021, 08:16
Sir,

I would suggest you first learn all the basics than try solving medium question from this forum UNTIMED. Then you can go for hard ones. Also in specific, where do you think you are lacking? in time management, concepts, ... ?

void wrote:
hello expert, i am having little trouble with high difficulty level question, any suggestion!!!
avatar
S
COolguy101
Senior Manager
Senior Manager
Joined: 23 Jan 2021
Posts: 294
Own Kudos [?]: 184 [0]
Given Kudos: 81
Concentration: , International Business
Send PM
Re: OA=AB [#permalink] New post   03 Jun 2021, 08:22
rx10 wrote:
Sir,

I would suggest you first learn all the basics than try solving medium question from this forum UNTIMED. Then you can go for hard ones. Also in specific, where do you think you are lacking? in time management, concepts, ... ?

void wrote:
hello expert, i am having little trouble with high difficulty level question, any suggestion!!!



YES, Absolutely
avatar
S
void
Senior Manager
Senior Manager
Joined: 03 Dec 2020
Posts: 440
Own Kudos [?]: 64 [0]
Given Kudos: 68
Send PM
Re: OA=AB [#permalink] New post   03 Jun 2021, 09:00
rx10 wrote:
Sir,

I would suggest you first learn all the basics than try solving medium question from this forum UNTIMED. Then you can go for hard ones. Also in specific, where do you think you are lacking? in time management, concepts, ... ?

void wrote:
hello expert, i am having little trouble with high difficulty level question, any suggestion!!!


thank you for replying, i think concept are little dusty ...please link comprehensive guide for quants.
User avatar
D
rx10
Retired Moderator
Joined: 02 Dec 2020
Posts: 1831
Own Kudos [?]: 2162 [2]
Given Kudos: 140
GRE 1: Q168 V157

GRE 2: Q167 V161
Send PM
Re: OA=AB [#permalink] New post   03 Jun 2021, 09:07
2
Here it is : https://gre.myprepclub.com/forum/gre-quant ... 22642.html

Feel free to ask anything. :)

void wrote:
rx10 wrote:
Sir,

I would suggest you first learn all the basics than try solving medium question from this forum UNTIMED. Then you can go for hard ones. Also in specific, where do you think you are lacking? in time management, concepts, ... ?

void wrote:
hello expert, i am having little trouble with high difficulty level question, any suggestion!!!


thank you for replying, i think concept are little dusty ...please link comprehensive guide for quants.
User avatar
D
Carcass
Verbal Expert
Joined: 18 Apr 2015
Posts: 33780
Own Kudos [?]: 40312 [1]
Given Kudos: 26600
Send PM
Re: OA=AB [#permalink] New post   03 Jun 2021, 09:11
1
Expert Reply
rx10

The rock 👍👍

Posted from my mobile device
avatar
S
Gocha
Manager
Manager
Joined: 25 Aug 2020
Posts: 80
Own Kudos [?]: 69 [1]
Given Kudos: 65
Send PM
Re: OA=AB [#permalink] New post   03 Jun 2021, 10:03
1
We do not have to calculate exact length.
Difference of y values of O and A is 3,
Difference of x values of O and A is 18,

Difference of x values of A and B is 3,
So difference of y values of A and B should be 18, and y value of A is 3 , so y values of B is 21.

21 > 18 so answer is A)
avatar
B
saumik
Intern
Intern
Joined: 29 Apr 2021
Posts: 24
Own Kudos [?]: 35 [0]
Given Kudos: 19
Send PM
Re: OA=AB [#permalink] New post   03 Jun 2021, 12:46
We won't have to venture into the distance/length formula if we know a key concept about the slopes of perpendicular lines.

The concept is - if two straight lines, with slopes m1 and m2 respectively, are perpendicular to each other, then m1*m2 = -1

The slope of OA, m1= 3-0/18-0 = 1/6
So the slope of OB, m2 will be: 1/6*m2 = -1; So, m2 = -6

Now we just have to plug in the value of m2 in the formula of slope for line AB to get the value of k.
3-k/18-15 = -6;
k = 21
So A is the answer.

It wouldn't take a minute to solve if you can use this concept.
I hope this helps! :D
User avatar
bumpbot
GRE Prep Club Legend
GRE Prep Club Legend
Joined: 07 Jan 2021
Posts: 5653
Own Kudos [?]: 81 [0]
Given Kudos: 0
Send PM
Re: OA=AB [#permalink] New post   08 Dec 2024, 08:50
Hello from the GRE Prep Club BumpBot!

Thanks to another GRE Prep 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.
Prep Club for GRE Bot
gmatclubot
Re: OA=AB [#permalink]
08 Dec 2024, 08:50
Moderators:
adewale223
GRE Instructor
132 posts
bronaugust
GRE Forum Moderator
37 posts
BrushMyQuant
Moderator
1141 posts
VibhuAnurag
GRE Instructor
234 posts
Nsp10
Moderator
39 posts
tyrant100
GRE Forum Moderator
125 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