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

It is currently 12 Dec 2019, 01:16

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

If x and y are two points on the number line what is the

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

Hide Tags

Find Similar Topics 
Manager
Manager
avatar
Joined: 05 Oct 2008
Posts: 216
If x and y are two points on the number line what is the  [#permalink]

Show Tags

New post Updated on: 24 Apr 2012, 05:47
2
18
00:00
A
B
C
D
E

Difficulty:

  65% (hard)

Question Stats:

51% (01:15) correct 49% (01:42) wrong based on 367 sessions

HideShow timer Statistics

If x and y are two points on the number line what is the value of x + y?

(1) 6 is halfway between x and y

(2) y = 2x

Originally posted by study on 24 Oct 2009, 00:04.
Last edited by Bunuel on 24 Apr 2012, 05:47, edited 1 time in total.
Edited the question and added the OA
Most Helpful Expert Reply
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 59685
Re: Number Line  [#permalink]

Show Tags

New post 24 Oct 2009, 09:44
6
6
I have to disagree with C. The answer to the question must be A.

If x and y are two points on the number line what is the value of x + y?

(1) 6 is halfway between x and y. On the GMAT we often see such statement and it can ALWAYS be expressed algebraically as \(6=\frac{x+y}{2}\) --> \(x+y=12\). Remember we are asked to determine the value of \(x+y\) not \(x\) and \(y\). Sufficient.

(2) y=2x. Clearly not sufficient

Answer: A.

Hope it's clear.
_________________
General Discussion
Director
Director
User avatar
Joined: 01 Apr 2008
Posts: 611
Name: Ronak Amin
Schools: IIM Lucknow (IPMX) - Class of 2014
Re: Number Line  [#permalink]

Show Tags

New post 24 Oct 2009, 05:04
IMO C.

stmt 1: x and y can be anything...(4,8) (5,7)....(-12,24).
stmt 2: y = 2x, again we can have (4,8) (5,10)...since 6 is not necessarily the midpoint of the line segment under consideration.

combining, 6+c = y = 2x, 6-c=x
adding these two equations, we get 12 = 3x => x = 4, y=8. This is the only possibility that satisfies both conditions.

However, if stmt 2 was something like: |y| = |2x|, then answer would have been E.
Manager
Manager
User avatar
Joined: 08 Oct 2009
Posts: 65
Location: Denmark, Europe
Schools: Darden Class of 2012
Re: Number Line  [#permalink]

Show Tags

New post 24 Oct 2009, 06:24
Yes, answer is C.

The first statement tells us that the average of X and Y is 6, i.e. (X+Y)/2=6 <=> X+Y=12
I.e. one equation in two unknowns => insufficient

The second equation is yet an equation in to unknowns => insufficient.

Combine the two statements to obtain 2x+3x = 3x = 12 <=> X=4 <=> Y=2*4=8.

So the answer is C.
Director
Director
User avatar
Joined: 01 Apr 2008
Posts: 611
Name: Ronak Amin
Schools: IIM Lucknow (IPMX) - Class of 2014
Re: Number Line  [#permalink]

Show Tags

New post 24 Oct 2009, 09:51
1
Agreed. It was my mistake. I didn't notice that all possible values of x and y will have a total =12, and that is what the question asks :(
Intern
Intern
avatar
Joined: 08 May 2011
Posts: 5
GMAT Date: 04-28-2012
If x and y are two points on the number line what is the  [#permalink]

Show Tags

New post 23 Apr 2012, 22:20
If x and y are points on the number line, what is the value of x + y ?
(1) 6 is halfway between x and y.
(2) y = 2x

Ans: A
When we say 6 is midway between x and y it means among x and y one number is 6 + m and other is 6 - m thus sum of x and y is (6+m)+(6-m) thus 12 irrespective of the value of m..
SVP
SVP
User avatar
Joined: 06 Sep 2013
Posts: 1545
Concentration: Finance
GMAT ToolKit User
Re: If x and y are two points on the number line what is the  [#permalink]

Show Tags

New post 28 Dec 2013, 05:48
study wrote:
If x and y are two points on the number line what is the value of x + y?

(1) 6 is halfway between x and y

(2) y = 2x


Question is asking for x+y

Statement 1 means that (x+y)/2 = 6

Hence x+y = 12

This is sufficient

Statement 2 is obviously not sufficient

Hence A

Cheers!
J :)
Manager
Manager
User avatar
Status: Please do not forget to give kudos if you like my post
Joined: 19 Sep 2008
Posts: 85
Location: United States (CA)
GMAT ToolKit User
Re: If x and y are two points on the number line what is the  [#permalink]

Show Tags

New post 20 Sep 2014, 18:22
Question is asking X+Y =>

isn't below always 12? ==< answer should be A.
stmt 1: x and y can be anything...(4,8) (5,7)....(-12,24).


Economist wrote:
IMO C.

stmt 1: x and y can be anything...(4,8) (5,7)....(-12,24).
stmt 2: y = 2x, again we can have (4,8) (5,10)...since 6 is not necessarily the midpoint of the line segment under consideration.

combining, 6+c = y = 2x, 6-c=x
adding these two equations, we get 12 = 3x => x = 4, y=8. This is the only possibility that satisfies both conditions.

However, if stmt 2 was something like: |y| = |2x|, then answer would have been E.
Director
Director
User avatar
G
Joined: 26 Oct 2016
Posts: 600
Location: United States
Concentration: Marketing, International Business
Schools: HBS '19
GMAT 1: 770 Q51 V44
GPA: 4
WE: Education (Education)
Re: If x and y are two points on the number line what is the  [#permalink]

Show Tags

New post 13 Feb 2017, 18:52
Whenever see a statement about AVERAGES (of which 'halfway' is one), you should automatically associate averages with SUMS. in other words, if you ever see a statement about an average, you should immediately translate that statement into the language of sums. to do so, just use the following equation:
average = sum / # of data points
or, equivalently,
sum = (average) x (# of data points)

statement (1):
this tells you that 6 is the average of x and y (or, (x + y)/2 = 6).
therefore,
sum of x + y = (average)(# of data points) = 6 x 2 = 12.
you can also do good old fashioned algebra to get this result: multiply both sides of (x + y)/2 = 6 by 2 to yield x + y = 12. in fact, that's probably easier on this problem, but it's important that you learn the average/sum formula so that you can apply it effortlessly to other situations (such as sums of 10, 20, or more numbers) on which an algebraic solution would be awkward or just plain impossible in a reasonable amount of time.

in any case, x + y = 12, so this is sufficient.

statement (2):
clearly insufficient by itself, since x and y could be huge (1 million and 2 million) or tiny (0.0001 and 0.0002).

Hence A.
_________________
Thanks & Regards,
Anaira Mitch
Intern
Intern
avatar
Joined: 08 Apr 2016
Posts: 3
Re: If x and y are two points on the number line what is the  [#permalink]

Show Tags

New post 21 Feb 2017, 02:06
anairamitch1804 wrote:
Whenever see a statement about AVERAGES (of which 'halfway' is one), you should automatically associate averages with SUMS. in other words, if you ever see a statement about an average, you should immediately translate that statement into the language of sums. to do so, just use the following equation:
average = sum / # of data points
or, equivalently,
sum = (average) x (# of data points)

statement (1):
this tells you that 6 is the average of x and y (or, (x + y)/2 = 6).
therefore,
sum of x + y = (average)(# of data points) = 6 x 2 = 12.
you can also do good old fashioned algebra to get this result: multiply both sides of (x + y)/2 = 6 by 2 to yield x + y = 12. in fact, that's probably easier on this problem, but it's important that you learn the average/sum formula so that you can apply it effortlessly to other situations (such as sums of 10, 20, or more numbers) on which an algebraic solution would be awkward or just plain impossible in a reasonable amount of time.

in any case, x + y = 12, so this is sufficient.

statement (2):
clearly insufficient by itself, since x and y could be huge (1 million and 2 million) or tiny (0.0001 and 0.0002).

Hence A.
anairamitch1804 wrote:
Whenever see a statement about AVERAGES (of which 'halfway' is one), you should automatically associate averages with SUMS. in other words, if you ever see a statement about an average, you should immediately translate that statement into the language of sums. to do so, just use the following equation:
average = sum / # of data points
or, equivalently,
sum = (average) x (# of data points)

statement (1):
this tells you that 6 is the average of x and y (or, (x + y)/2 = 6).
therefore,
sum of x + y = (average)(# of data points) = 6 x 2 = 12.
you can also do good old fashioned algebra to get this result: multiply both sides of (x + y)/2 = 6 by 2 to yield x + y = 12. in fact, that's probably easier on this problem, but it's important that you learn the average/sum formula so that you can apply it effortlessly to other situations (such as sums of 10, 20, or more numbers) on which an algebraic solution would be awkward or just plain impossible in a reasonable amount of time.

in any case, x + y = 12, so this is sufficient.

statement (2):
clearly insufficient by itself, since x and y could be huge (1 million and 2 million) or tiny (0.0001 and 0.0002).

Hence A.


What if x=-5 and y = 22 the sum is 17. If x= -10 and y = 32 the sum is 22. Statement never said that the numbers are +ve. Also the stat 1 and 2 speak only about alzebra not about absolute distance.
Please help. I think the answer is C as it gives unique solution ie 4 and 8.
GMAT Club Legend
GMAT Club Legend
User avatar
V
Joined: 12 Sep 2015
Posts: 4134
Location: Canada
Re: If x and y are two points on the number line what is the  [#permalink]

Show Tags

New post 06 Apr 2019, 07:48
Top Contributor
study wrote:
If x and y are two points on the number line what is the value of x + y?

(1) 6 is halfway between x and y

(2) y = 2x


Target question: What is the value of x + y?

Statement 1: 6 is halfway between x and y.
KEY CONCEPT: The average (arithmetic mean) of 2 numbers is HALFWAY between those 2 numbers.
For example, the average of 1 and 9 is 5. Notice that 5 is HALFWAY between 1 and 9.

So, statement is telling us that 6 is the average of x and y
In other words, (x + y)/2 = 6
This means x + y = 12
The answer to the target question is x + y = 12
Since we can answer the target question with certainty, statement 1 is SUFFICIENT

Statement 2: y = 2x
There are infinitely many values of x and y that satisfy statement 2. Here are two:
Case a: x = 1 and y = 2. In this case, the answer to the target question is x + y = 1 + 2 = 3
Case b: x = 3 and y = 6. In this case, the answer to the target question is x + y = 3 + 6 = 9
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Answer: A

Cheers,
Brent

RELATED VIDEO FROM MY COURSE

_________________
Test confidently with gmatprepnow.com
Image
Director
Director
User avatar
V
Joined: 24 Oct 2016
Posts: 586
GMAT 1: 670 Q46 V36
GMAT 2: 690 Q47 V38
Re: If x and y are two points on the number line what is the  [#permalink]

Show Tags

New post 02 Sep 2019, 15:54
study wrote:
If x and y are two points on the number line what is the value of x + y?

(1) 6 is halfway between x and y

(2) y = 2x


A) Consider cases:
x=5, y=7 => x+y = 12
x=-1, y=13 => x+y = 12
Sufficient

B) x + 2x = 3x = ? => Not sufficient

ANSWER: A
GMAT Club Bot
Re: If x and y are two points on the number line what is the   [#permalink] 02 Sep 2019, 15:54
Display posts from previous: Sort by

If x and y are two points on the number line what is the

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





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