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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

The difference between John's and Paul's heights is twice [#permalink]

Show Tags

06 Apr 2012, 11:35

4

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

75% (hard)

Question Stats:

43% (02:04) correct
57% (00:51) wrong based on 150 sessions

HideShow timer Statistics

The difference between John's and Paul's heights is twice the difference between John's and Thom's heights. If John is the tallest, what is the average (arithmetic mean) height of the three?

The difference between John's and Paul's heights is twice the difference between John's and Thom's heights. If John is the tallest, what is the average (arithmetic mean) height of the three?

Re: The difference between John's and Paul's heights is twice [#permalink]

Show Tags

14 Sep 2012, 06:53

Bunuel wrote:

The difference between John's and Paul's heights is twice the difference between John's and Thom's heights. If John is the tallest, what is the average (arithmetic mean) height of the three?

The difference between John's and Paul's heights is twice the difference between John's and Thom's heights. If John is the tallest, what is the average (arithmetic mean) height of the three?

Re: The difference between John's and Paul's heights is twice [#permalink]

Show Tags

14 Sep 2012, 07:33

rovshan85 wrote:

The difference between John's and Paul's heights is twice the difference between John's and Thom's heights. If John is the tallest, what is the average (arithmetic mean) height of the three?

(1) Paul is 163 centimeters tall.

(2) Thom is 173 centimeters tall.

If we denote the heights by J, P and T, we can write J = P + 2x and J = T + x for some positive integer x. Then, P + 2x = T + x, or P = T - x. So, the three heights are T - x, T, and T + x. Obviously, their average is T.

We can immediately see that (1) is not sufficient, but (2) is.

Answer B.
_________________

PhD in Applied Mathematics Love GMAT Quant questions and running.

Re: The difference between John's and Paul's heights is twice [#permalink]

Show Tags

14 Sep 2012, 07:54

Bunuel wrote:

fameatop wrote:

Bunuel wrote:

The difference between John's and Paul's heights is twice the difference between John's and Thom's heights. If John is the tallest, what is the average (arithmetic mean) height of the three?

(1) Paul is 163 centimeters tall --> P=163. Not sufficient.

(2) Thom is 173 centimeters tall --> directly gives the value of T. Sufficient.

Answer: B.

Hi Bunuel,

I have a doubt in this question. Kindly correct me if i am wrong.

Let the height of John Paul Tom 5x 3x 4x John - Paul = 2(John - Tom) 5x-3x = 2 (5x-4x) LHS = RHS Average height of 3 = 12x/3 = 4x

(1) 3x = 163----> we can find the value of 4x as there is no restriction on the value x can take.---> Sufficient (2) 4x = 173 ----> Sufficient

Answer D

Can you tell me WHY i am wrong wrt OA

Waiting for response.

You cannot arbitrary assume that the heights are 5x, 3x and 4x. Why not 10x, 6x, and 8x?

It doesn't make any difference whether we are taking 5x,3x& 4x or 10x, 6x, and 8x Because average in first case is 4x & in second case is 8x If we are given in first case 3x = 163 & in second case 6x = 163 We want the value of 4x in first case & 8x in second case In Both cases answer will be same which is 163*4/3

Kindly enlighten
_________________

If you like my Question/Explanation or the contribution, Kindly appreciate by pressing KUDOS. Kudos always maximizes GMATCLUB worth-Game Theory

If you have any question regarding my post, kindly pm me or else I won't be able to reply

Re: The difference between John's and Paul's heights is twice [#permalink]

Show Tags

14 Sep 2012, 08:46

fameatop wrote:

Hi Bunuel,

I have a doubt in this question. Kindly correct me if i am wrong.

Let the height of John Paul Tom 5x 3x 4x John - Paul = 2(John - Tom) 5x-3x = 2 (5x-4x) LHS = RHS Average height of 3 = 12x/3 = 4x

(1) 3x = 163----> we can find the value of 4x as there is no restriction on the value x can take.---> Sufficient (2) 4x = 173 ----> Sufficient

Answer D

Can you tell me WHY i am wrong wrt OA

Waiting for response.[/quote]

You cannot arbitrary assume that the heights are 5x, 3x and 4x. Why not 10x, 6x, and 8x?[/quote]

It doesn't make any difference whether we are taking 5x,3x& 4x or 10x, 6x, and 8x Because average in first case is 4x & in second case is 8x If we are given in first case 3x = 163 & in second case 6x = 163 We want the value of 4x in first case & 8x in second case In Both cases answer will be same which is 163*4/3

Re: The difference between John's and Paul's heights is twice [#permalink]

Show Tags

14 Sep 2012, 09:19

EvaJager wrote:

fameatop wrote:

You cannot arbitrary assume that the heights are 5x, 3x and 4x. Why not 10x, 6x, and 8x?

It doesn't make any difference whether we are taking 5x,3x& 4x or 10x, 6x, and 8x Because average in first case is 4x & in second case is 8x If we are given in first case 3x = 163 & in second case 6x = 163 We want the value of 4x in first case & 8x in second case In Both cases answer will be same which is 163*4/3

Kindly enlighten[/quote]

All you can assume is that the three heights are T - x, T, and T + x for some positive x, where T is Thom's height. See my previous post: the-difference-between-john-s-and-paul-s-heights-is-twice-130320.html#p1121568 Take the three heights 163, 173, and 183. 183 - 163 = 20 = 2(183 - 173) Is 163/3 = 173/4 = 183/5? No![/quote]

If you go by my method using option (1), the three heights will be 271.66, 163, 217.3 & the differences in height is 108.66, 54.33 which satisfies the original statement.

I could be wrong Had the question stated that the heights are integer values, but nothing of such sort is mentioned. Why i am wrong?

Waiting 4 reply
_________________

If you like my Question/Explanation or the contribution, Kindly appreciate by pressing KUDOS. Kudos always maximizes GMATCLUB worth-Game Theory

If you have any question regarding my post, kindly pm me or else I won't be able to reply

Re: The difference between John's and Paul's heights is twice [#permalink]

Show Tags

14 Sep 2012, 09:35

fameatop wrote:

EvaJager wrote:

fameatop wrote:

You cannot arbitrary assume that the heights are 5x, 3x and 4x. Why not 10x, 6x, and 8x?

It doesn't make any difference whether we are taking 5x,3x& 4x or 10x, 6x, and 8x Because average in first case is 4x & in second case is 8x If we are given in first case 3x = 163 & in second case 6x = 163 We want the value of 4x in first case & 8x in second case In Both cases answer will be same which is 163*4/3

Kindly enlighten

All you can assume is that the three heights are T - x, T, and T + x for some positive x, where T is Thom's height. See my previous post: the-difference-between-john-s-and-paul-s-heights-is-twice-130320.html#p1121568 Take the three heights 163, 173, and 183. 183 - 163 = 20 = 2(183 - 173) Is 163/3 = 173/4 = 183/5? No![/quote]

If you go by my method using option (1), the three heights will be 271.66, 163, 217.3 & the differences in height is 108.66, 54.33 which satisfies the original statement.

I could be wrong Had the question stated that the heights are integer values, but nothing of such sort is mentioned. Why i am wrong?

Waiting 4 reply[/quote]

It is a DS question. Also the triplet 163, 173, 183 satisfies the requirements. So, how can (1) be sufficient? _________________

PhD in Applied Mathematics Love GMAT Quant questions and running.

Re: The difference between John's and Paul's heights is twice [#permalink]

Show Tags

22 Mar 2013, 06:38

fameatop wrote:

Bunuel wrote:

The difference between John's and Paul's heights is twice the difference between John's and Thom's heights. If John is the tallest, what is the average (arithmetic mean) height of the three?

Happy New Year everyone! Before I get started on this post, and well, restarted on this blog in general, I wanted to mention something. For the past several months...

It’s quickly approaching two years since I last wrote anything on this blog. A lot has happened since then. When I last posted, I had just gotten back from...

Happy 2017! Here is another update, 7 months later. With this pace I might add only one more post before the end of the GSB! However, I promised that...