• Get 300+ Practice Questions

Available with Beat the GMAT members only code

• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• Award-winning private GMAT tutoring
Register now and save up to \$200

Available with Beat the GMAT members only code

• Reach higher with Artificial Intelligence. Guaranteed
Now free for 30 days

Available with Beat the GMAT members only code

the number line shown contains 3 points

This topic has 4 expert replies and 3 member replies
peter456 Junior | Next Rank: 30 Posts
Joined
20 Sep 2015
Posted:
24 messages

the number line shown contains 3 points

Thu Mar 03, 2016 8:28 am
The number line shown contains 3 points R, S, and T, whose coordinates have absolute values r, s, and t, respectively. Which of the following equals the average 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
Sorry I can't draw but just an idea;
<----R------0----S----T---->
Since the coordinates are given in absolute values, I felt their average
is simply (r+s+t)/3

Last edited by peter456 on Sun Mar 06, 2016 6:31 pm; edited 1 time in total

GMAT/MBA Expert

Rich.C@EMPOWERgmat.com Elite Legendary Member
Joined
23 Jun 2013
Posted:
9316 messages
Followed by:
478 members
2867
GMAT Score:
800
Fri Mar 11, 2016 9:34 am
Hi peter456,

The prompt asks for the average of R, S and T. From the number line, we can see that R is NEGATIVE though, so that is going to impact the sum of those three variables.

The variables r, s and t are all POSITIVE, since they're the respective absolute values of R, S and T. If you were taking the average of THESE 3 variables, the result would ALWAYS be positive. When taking the average of R, S and T though, the average could end up negative or 0. Thus, Answer D cannot be correct.

GMAT assassins aren't born, they're made,
Rich

_________________
Contact Rich at Rich.C@empowergmat.com

GMAT/MBA Expert

Jeff@TargetTestPrep GMAT Instructor
Joined
09 Apr 2015
Posted:
894 messages
Followed by:
12 members
39
Tue Dec 19, 2017 7:05 am
peter456 wrote:
The number line shown contains 3 points R, S, and T, whose coordinates have absolute values r, s, and t, respectively. Which of the following equals the average 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

We can let R, S, and T be the actual values. Thus, we want to determine the value of (R + S + T)/3. Since S and T are positive, S = s and T = t. However, since R is negative, R = -r. Thus, the average becomes:

(-r + s + t)/3

(s + t - r)/3

_________________
Jeffrey Miller Head of GMAT Instruction

GMAT/MBA Expert

Rich.C@EMPOWERgmat.com Elite Legendary Member
Joined
23 Jun 2013
Posted:
9316 messages
Followed by:
478 members
2867
GMAT Score:
800
Thu Mar 03, 2016 9:47 am
Hi peter456,

This question can be solved by TESTing VALUES.

Based on their positions on the number line, we know that S and T are POSITIVE and R is NEGATIVE, so let's TEST...

R = -3
S = 1
T = 2

Since r, s and t are the ABSOLUTE VALUES of those 3 numbers, we have...

r = 3
s = 1
t = 2

The question asks for the AVERAGE of R, S and T, so we're looking for an answer that equals (-3 + 1 + 2)/3 = 0/3 = 0.

(A) s = 3 NOT a match
(B) s + t + r = 6 NOT a match
(C) (r-s-t)/3 = 0 This IS a match
(D) (r+s+t)/3 = 2 NOT a match
(E) (r+s-t)/3 = 2/3 NOT a match

GMAT assassins aren't born, they're made,
Rich

_________________
Contact Rich at Rich.C@empowergmat.com

peter456 Junior | Next Rank: 30 Posts
Joined
20 Sep 2015
Posted:
24 messages
Sun Mar 06, 2016 6:24 pm
Rich.C@EMPOWERgmat.com wrote:
Hi peter456,

This question can be solved by TESTing VALUES.

Based on their positions on the number line, we know that S and T are POSITIVE and R is NEGATIVE, so let's TEST...

R = -3
S = 1
T = 2

Since r, s and t are the ABSOLUTE VALUES of those 3 numbers, we have...

r = 3
s = 1
t = 2

The question asks for the AVERAGE of R, S and T, so we're looking for an answer that equals (-3 + 1 + 2)/3 = 0/3 = 0.

(A) s = 3 NOT a match
(B) s + t + r = 6 NOT a match
(C) (r-s-t)/3 = 0 This IS a match
(D) (r+s+t)/3 = 2 NOT a match
(E) (r+s-t)/3 = 2/3 NOT a match

GMAT assassins aren't born, they're made,
Rich
Hi EmpowerGmat,
The OA is not C; hwever, option E should be (s+t-r)/3, the OA.

Could u please revisit this question?

Marty Murray Legendary Member
Joined
03 Feb 2014
Posted:
2050 messages
Followed by:
131 members
955
GMAT Score:
800
Sun Mar 06, 2016 8:57 pm
peter456 wrote:
The number line shown contains 3 points R, S, and T, whose coordinates have absolute values r, s, and t, respectively. Which of the following equals the average 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
Sorry I can't draw but just an idea;
<----R------0----S----T---->
Since the coordinates are given in absolute values, I felt their average
is simply (r+s+t)/3
We need to find the average of the coordinates. Average = Sum/Number

The absolute value of a number is the POSITIVE DISTANCE between that number and zero.

S and T are to the right of 0 on the number line. So the values of their coordinates are greater than 0. So the values of s and t, which are ABSOLUTE values of the coordinates, are the same as the values of the coordinates.

R is to the left of 0 on the number line. So the value of R's coordinate is less than 0. r is an absolute value. So the value of R's coordinate, which is a negative number, is -r.

To find the average of the values of the three coordinates, find the sum of the coordinates and divide by the number of coordinates.

(s + t - r)/3 = the average of the coordinates

_________________
Marty Murray
GMAT Coach
m.w.murray@hotmail.com
https://infinitemindprep.com/
In Person in the New York Area and Online Worldwide

GMAT/MBA Expert

Rich.C@EMPOWERgmat.com Elite Legendary Member
Joined
23 Jun 2013
Posted:
9316 messages
Followed by:
478 members
2867
GMAT Score:
800
Sun Mar 06, 2016 11:10 pm
Hi peter456,

Since you've made an edit to the original question, I'm curious if you fixed any typos in the answer choices (the original Answer E that I copied from your post doesn't match the current Answer E that is listed there). Regardless, with the "new" Answer E, and the 3 numbers that I chose to TEST, we would have TWO answers that match: BOTH Answer C and Answer E.

In a situation in which more than one answer appears correct, you have to TEST a "new" set of VALUES, although you don't necessarily have to change all of them. In this case, you can change just the value of R and r and you'll get the correct answer.

If we TEST:

R = -4
S = 1
T = 2

Then we have....

r = 4
s = 1
t = 2

The average of R, S and T equals -1/3, so we're looking for THAT result in Answers C and E.

(C)(r-s-t)/3 = +1/3 NOT a match

(E)(s+t-r)/3 = -1/3 This IS a match

GMAT assassins aren't born, they're made,
Rich

_________________
Contact Rich at Rich.C@empowergmat.com

peter456 Junior | Next Rank: 30 Posts
Joined
20 Sep 2015
Posted:
24 messages
Fri Mar 11, 2016 9:20 am
My line of reasoning is that since r, s, and t are non-zero positive values, their average should be
(r+ s + t)/ 3...given that |R| = r; |S|=s; |T|=t

Kindly point where am making errors

Thank you

Best Conversation Starters

1 lheiannie07 76 topics
2 LUANDATO 59 topics
3 ardz24 52 topics
4 AAPL 46 topics
5 M7MBA 45 topics
See More Top Beat The GMAT Members...

Most Active Experts

1 Jeff@TargetTestPrep

Target Test Prep

141 posts
2 Brent@GMATPrepNow

GMAT Prep Now Teacher

136 posts
3 GMATGuruNY

The Princeton Review Teacher

134 posts
4 Rich.C@EMPOWERgma...

EMPOWERgmat

129 posts
5 Scott@TargetTestPrep

Target Test Prep

110 posts
See More Top Beat The GMAT Experts