It is currently 20 Oct 2017, 07:48

### 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

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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# The number line shown contains three points R, S, and T, whose coordin

Author Message
TAGS:

### Hide Tags

Senior Manager
Joined: 03 Mar 2010
Posts: 422

Kudos [?]: 361 [5], given: 22

Schools: Simon '16 (M)
The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

01 May 2011, 02:51
5
KUDOS
24
This post was
BOOKMARKED
00:00

Difficulty:

15% (low)

Question Stats:

64% (00:39) correct 36% (00:41) wrong based on 1132 sessions

### HideShow timer Statistics

The number line shown contains three points R, S, and T, whose coordinates have absolute values r, s, and t, respectively. Which of the following equals the average (arithmetic mean) of the coordinates of the points R, S, and T ?

A. s
B. s + t - r
C. (r - s - t)/3
D. (r + s + t)/3
E. (s + t - r)/3

[Reveal] Spoiler:
Attachment:

2015-09-18_1954.png [ 5.82 KiB | Viewed 11549 times ]
[Reveal] Spoiler: OA

_________________

My dad once said to me: Son, nothing succeeds like success.

Last edited by Bunuel on 18 Sep 2015, 08:55, edited 1 time in total.
Renamed the topic, edited the question and added the OA.

Kudos [?]: 361 [5], given: 22

VP
Status: There is always something new !!
Affiliations: PMI,QAI Global,eXampleCG
Joined: 08 May 2009
Posts: 1285

Kudos [?]: 282 [0], given: 10

Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

01 May 2011, 03:18
As R is to the right of the origin,essentially it has negative value.
therefore arithmetic mean = (s+t-r)/3 will be the right expression as S and T are positive numbers.
Hence E.
_________________

Visit -- http://www.sustainable-sphere.com/
Promote Green Business,Sustainable Living and Green Earth !!

Kudos [?]: 282 [0], given: 10

Retired Moderator
Joined: 02 Sep 2010
Posts: 793

Kudos [?]: 1186 [2], given: 25

Location: London
Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

01 May 2011, 04:34
2
KUDOS
3
This post was
BOOKMARKED
The arithmetic mean of three numbers x y z is (x+y+z)/3

In this case we know that the numbers are s, t, -r (since r is the absolute value of a negative number ... and s,t are the absolute values of positive numbers)

Hence mean is (s+t-r)/3

Posted from my mobile device
_________________

Kudos [?]: 1186 [2], given: 25

Senior Manager
Joined: 03 Mar 2010
Posts: 422

Kudos [?]: 361 [2], given: 22

Schools: Simon '16 (M)
Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

01 May 2011, 04:51
2
KUDOS
shrouded1 wrote:
In this case we know that the numbers are s, t, -r (since r is the absolute value of a negative number

$$|r| = r when r > 0$$
$$= -r when r < 0$$
and since r < 0, it should be -r
Am i correct?
_________________

My dad once said to me: Son, nothing succeeds like success.

Kudos [?]: 361 [2], given: 22

Retired Moderator
Joined: 02 Sep 2010
Posts: 793

Kudos [?]: 1186 [0], given: 25

Location: London
Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

01 May 2011, 06:38
Spot on

Posted from my mobile device
_________________

Kudos [?]: 1186 [0], given: 25

Director
Joined: 10 Mar 2013
Posts: 593

Kudos [?]: 460 [4], given: 200

Location: Germany
Concentration: Finance, Entrepreneurship
GMAT 1: 580 Q46 V24
GPA: 3.88
WE: Information Technology (Consulting)
Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

18 Sep 2015, 01:20
4
KUDOS
I don't really get the logic here. The absolute value of any number is > 0.
r is a negative number on the line I-r I = r. The only explanation for this solution I see is that, the absolute value of -r is >0, but the value of r is negative (within the absolute brackets), and in the calculation of average we are using r and not an absolute value of r please correct if I'm wrong.
_________________

When you’re up, your friends know who you are. When you’re down, you know who your friends are.

800Score ONLY QUANT CAT1 51, CAT2 50, CAT3 50
GMAT PREP 670
MGMAT CAT 630
KAPLAN CAT 660

Kudos [?]: 460 [4], given: 200

Manager
Joined: 29 Jul 2015
Posts: 159

Kudos [?]: 184 [4], given: 59

Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

18 Sep 2015, 11:49
4
KUDOS
BrainLab wrote:
I don't really get the logic here. The absolute value of any number is > 0.
r is a negative number on the line I-r I = r. The only explanation for this solution I see is that, the absolute value of -r is >0, but the value of r is negative (within the absolute brackets), and in the calculation of average we are using r and not an absolute value of r please correct if I'm wrong.

I was wondering the same thing. I marked D as answer taking absolute values.
Need some explanation here.

Kudos [?]: 184 [4], given: 59

Manager
Joined: 13 Mar 2013
Posts: 178

Kudos [?]: 75 [0], given: 25

Location: United States
GPA: 3.5
WE: Engineering (Telecommunications)
Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

20 Sep 2015, 01:22
Hi Bunuel ,

would please explain the concept for absolute number and details explain solution of this question .

Regards,
_________________

Regards ,

Kudos [?]: 75 [0], given: 25

Intern
Joined: 05 Jul 2013
Posts: 28

Kudos [?]: 6 [1], given: 375

GMAT 1: 710 Q48 V40
GPA: 3
Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

30 Sep 2015, 01:03
1
KUDOS
I am wondering the same thing ...otherwise why would the question mention absolute values if you want us to take the sign of the number into consideration. Absolute values meaning all are positive. And it asks what is the average of the co-ordinates and the co-ordinates are given to be absolute values.

Would be grateful if someone can shed some light on this. Thnx

Kudos [?]: 6 [1], given: 375

Intern
Joined: 09 Sep 2015
Posts: 2

Kudos [?]: 2 [2], given: 0

Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

17 Oct 2015, 02:43
2
KUDOS
Hi, I would also like to clarify this solution. If r is the absolute value of R and R is -R then why is the co-ordinate -r? If it is an absolute value it cannot be a negative number. Please explain?

Kudos [?]: 2 [2], given: 0

Math Expert
Joined: 02 Sep 2009
Posts: 41891

Kudos [?]: 128979 [5], given: 12185

Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

18 Oct 2015, 09:59
5
KUDOS
Expert's post
4
This post was
BOOKMARKED
mrai87 wrote:

The number line shown contains three points R, S, and T, whose coordinates have absolute values r, s, and t, respectively. Which of the following equals the average (arithmetic mean) of the coordinates of the points R, S, and T ?

A. s
B. s + t - r
C. (r - s - t)/3
D. (r + s + t)/3
E. (s + t - r)/3

Hi, I would also like to clarify this solution. If r is the absolute value of R and R is -R then why is the co-ordinate -r? If it is an absolute value it cannot be a negative number. Please explain?

Say R = -3, S = 1 and T = 2. In this case r = |-3| = 3, s = 1, and t = 2. The average of the coordinates of the points R, S, and T would be (2 + 1 + (-3))/3 so, (s + t - r)/3.
_________________

Kudos [?]: 128979 [5], given: 12185

Intern
Joined: 09 Sep 2015
Posts: 2

Kudos [?]: 2 [0], given: 0

Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

16 Nov 2015, 17:55
thank you Bunuel

Kudos [?]: 2 [0], given: 0

Director
Status: Tutor - BrushMyQuant
Joined: 05 Apr 2011
Posts: 622

Kudos [?]: 768 [0], given: 59

Location: India
Concentration: Finance, Marketing
Schools: XLRI (A)
GMAT 1: 700 Q51 V31
GPA: 3
WE: Information Technology (Computer Software)
Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

21 Nov 2015, 08:29
Thank you

The number line shown contains three points R, S, and T, whose coordinates have absolute values r, s, and t, respectively. Which of the following equals the average (arithmetic mean) of the coordinates of the points R, S, and T ?

A. s
B. s + t - r
C. (r - s - t)/3
D. (r + s + t)/3
E. (s + t - r)/3

[Reveal] Spoiler:
Attachment:
2015-09-18_1954.png

_________________

Ankit

Check my Tutoring Site -> Brush My Quant

GMAT Quant Tutor
How to start GMAT preparations?
How to Improve Quant Score?
Gmatclub Topic Tags
Check out my GMAT debrief

How to Solve :
Statistics || Reflection of a line || Remainder Problems || Inequalities

Kudos [?]: 768 [0], given: 59

GMAT Club Legend
Joined: 09 Sep 2013
Posts: 16634

Kudos [?]: 273 [0], given: 0

Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

30 Nov 2016, 05:10
Hello from the GMAT Club BumpBot!

Thanks to another GMAT 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.
_________________

Kudos [?]: 273 [0], given: 0

Manager
Joined: 31 Dec 2016
Posts: 91

Kudos [?]: 9 [1], given: 22

The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

31 Dec 2016, 09:41
1
KUDOS
I didn't find the answers above very helpful and they were all confusing. Hopefully this one is less so.

Here is an answer which to me makes more sense. We are shown a number line. An absolute value can never be negative on a number line unless the negative is outside the brackets. Therefore if R is shown as -3 on the number line it would be shown as -[-3] and if R is +3 then it would be shown as -[3]. In either case the negative outside the bracket will move it into the negative position on the number line. Therefore all the Math is S + T - +R which is (S+T-R)/ 3. So the absolute value of R is positive but because it's shown on a number line it has to have a negative infront of it. Had the Question simply asked the absolute Value of [3] +[2] +[-2] the answer would be (3+2-2) /3 but since it showed us the numbers on the number line we can conclude the number are something like [3] + [2] + -[2]

Kudos [?]: 9 [1], given: 22

Intern
Joined: 24 Nov 2016
Posts: 9

Kudos [?]: [0], given: 6

Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

31 Mar 2017, 04:55
SamBoyle wrote:
I didn't find the answers above very helpful and they were all confusing. Hopefully this one is less so.

Here is an answer which to me makes more sense. We are shown a number line. An absolute value can never be negative on a number line unless the negative is outside the brackets. Therefore if R is shown as -3 on the number line it would be shown as -[-3] and if R is +3 then it would be shown as -[3]. In either case the negative outside the bracket will move it into the negative position on the number line. Therefore all the Math is S + T - +R which is (S+T-R)/ 3. So the absolute value of R is positive but because it's shown on a number line it has to have a negative infront of it. Had the Question simply asked the absolute Value of [3] +[2] +[-2] the answer would be (3+2-2) /3 but since it showed us the numbers on the number line we can conclude the number are something like [3] + [2] + -[2]

Hi Sam,

The question is asking for you to find the average of "r, s and t" that matches the average of "R, S and T."

(i) If RST = [-4, 1, 2], the average equals (-4+1+2)/3 = -1/3;
(ii) Then, |rst| = [4, 1, 2] and the only answer matching the average of RST is "(E) s+t-r/3" = (1+2-4)/3 = -1/3"

Rgds

Kudos [?]: [0], given: 6

Intern
Joined: 03 Oct 2016
Posts: 1

Kudos [?]: [0], given: 3

Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

26 Apr 2017, 09:43
I am still confused about this absolute value still being negative in the end. If the question had been exactly the same but without mentionning absolute values:
Quote:
whose coordinates have values r, s, and t

Quote:
whose coordinates have absolute values r, s, and t

Would the result be the same ?

Kudos [?]: [0], given: 3

Intern
Joined: 18 May 2017
Posts: 16

Kudos [?]: 0 [0], given: 113

WE: Corporate Finance (Health Care)
Re: The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

23 May 2017, 11:06
This question is kind of Deceptive . you can still have (+(-R)+S+T)/3 to make D correct . E could also be rationalized like (S+T-(+R))/3 . This is why I hate the GMAT . We are arguing semantics/Syntax . Unless I am just dumb and don't comprehend.

Kudos [?]: 0 [0], given: 113

Intern
Joined: 28 Dec 2010
Posts: 23

Kudos [?]: 44 [0], given: 337

The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

23 Jul 2017, 17:49
According to the question - "coordinates have absolute values r, s, and t" -> which implies the distance of R, S & T from the origin "zero" is given i.e. the magnitude.

Since |x| = -(x) for x < 0 and |x| = (x) for x>=0.

example:

consider R = -4, S=2, t=3 based on the question

we are given, absolute value of R --> r = -(-4) = 4
we are given, absolute value of S --> s = (2) = 3
we are given, absolute value of T --> t = (3) = 3

Now, the question is asking for a mean of all these coordinates. Since the points are distributed across origin 0. In order to calculate the mean we will have to add the coordinates then divide by the number of coordinates. As the coordinate R is on the -ve side of origin we will have to use a -ve sign i.e. -r

Thus, the answer will be (s+t-r)/3

Note: Assuming if we are not given the absolute value information we can calculate the mean of the coordinates based on the placement of the coordinates on the number line, the only caveat being that the coordinates should be clearly mentioned w.r.t to the origin on the number line.
Attachments

absolute_value.JPG [ 16.74 KiB | Viewed 1860 times ]

Last edited by gary391 on 24 Jul 2017, 12:18, edited 6 times in total.

Kudos [?]: 44 [0], given: 337

Director
Joined: 22 May 2016
Posts: 816

Kudos [?]: 265 [0], given: 552

The number line shown contains three points R, S, and T, whose coordin [#permalink]

### Show Tags

24 Jul 2017, 07:16
NanaA wrote:
This question is kind of Deceptive . you can still have (+(-R)+S+T)/3 to make D correct . E could also be rationalized like (S+T-(+R))/3 . This is why I hate the GMAT . We are arguing semantics/Syntax . Unless I am just dumb and don't comprehend.

You certainly are not dumb; your intelligence led you to see that the way absolute value is often taught, and the way it shows up here, seem incongruent.

I'll avoid the semantics / syntax categorization, except to say that, overly simplified, the issue is what "absolute value" denotes.

In this case, we have a negative variable, -r. It might help to memorize this rule: If r is negative, i.e. if r < 0, then |r| = -r.

NOVA explains the latter equality's seeming contradiction. "This often confuses students because the absolute value is positive, but the -r appears to be negative." The latter isn't negative.

"It is actually positive -- it is the negative of a negative number, which is positive."

The authors also write, "Another way to view this [seeming contradiction] is

|x| = -x = (-1)(a negative number) = a positive number."

For the quoted material as well as the full explanation from NOVA, see these two sites (the second is more thorough):

Nova Press,GMAT Math Strategies, "Absolute Value," (scroll down a long way)
http://novapress.net/gmat/gmat-strategies/gmat-math-strategies/ (accessed 7/24/17), and

"Absolute Value,"

I had to teach myself Algebra 1 and 2. In the U.S., my textbooks were (and may still be) unhelpful at best with this issue. My eyes were crossed. Sometimes they still are. I understand, but not always.

So I memorized the rule and the method for solving, and left it at that.

For this problem, I assigned values to the variables and calculated the mean with numbers that had both the intuitively correct signs, and, given the rule, the mathematically correct signs. (-1 + 2 + 5)/3 = mean of 2.

Here is another link to a great post that might help, Bunuel, Absolute Value, Tips and Tricks,
https://gmatclub.com/forum/absolute-value-tips-and-hints-175002.html

Hope this helps.

Kudos [?]: 265 [0], given: 552

The number line shown contains three points R, S, and T, whose coordin   [#permalink] 24 Jul 2017, 07:16

Go to page    1   2    Next  [ 22 posts ]

Display posts from previous: Sort by