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

It is currently 16 Aug 2018, 16:48

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 the average (arithmetic mean) height of Bob, John and Tom is 180 cm

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

Hide Tags

Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 6020
GMAT 1: 760 Q51 V42
GPA: 3.82
Premium Member
If the average (arithmetic mean) height of Bob, John and Tom is 180 cm  [#permalink]

Show Tags

New post 02 Aug 2018, 00:39
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

64% (00:59) correct 36% (01:09) wrong based on 50 sessions

HideShow timer Statistics

[Math Revolution GMAT math practice question]

If the average (arithmetic mean) height of Bob, John and Tom is 180 cm, what is their median height?

1) Bob’s height is 175cm.
2) John’s height is 180cm.

_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $99 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Math Revolution Discount CodesKaplan GMAT Prep Discount CodesJamboree Discount Codes
RC Moderator
User avatar
G
Status: Perfecting myself for GMAT
Joined: 22 May 2017
Posts: 423
Concentration: Nonprofit
Schools: Haas '21
GPA: 4
WE: Engineering (Computer Software)
GMAT ToolKit User Premium Member CAT Tests
Re: If the average (arithmetic mean) height of Bob, John and Tom is 180 cm  [#permalink]

Show Tags

New post 02 Aug 2018, 02:26
1
To find the median height of John, Tom and Bob

The average (arithmetic mean) height of Bob, John and Tom is 180 cm

=> Sum of heights of Bob, John and Tom = 180 * 3 = 540

Statement 1

Bob’s height is 175cm

=> Sum of heights of John and Tom = \(540 - 175 = 365\)

The height of John and Tom can be 178 and 187 making the median height 178 OR

The height of John and Tom can be 170 and 195 making the median height 175

Statement 1 is not sufficient

Statement 2

John’s height is 180cm

=> Sum of heights of Bob and Tom = \(540 - 180 = 360\)

Now only two cases are possible

Case 1)

Heights of John, Bob and Tom are equal to 180 and the median height = 180

Case 2)

The height of Bob/Tom can be < 180 and height of Tom/Bob can be > 180 making the median height 180

The median height in both cases is 180

Statement 2 is sufficient

Hence option B
_________________

If you like my post press kudos +1

New - RC Butler - 2 RC's everyday

Tag me in RC questions if you need help. Please provide your analysis of the question in the post along with the tag.

Director
Director
User avatar
S
Joined: 20 Feb 2015
Posts: 512
Concentration: Strategy, General Management
Premium Member
If the average (arithmetic mean) height of Bob, John and Tom is 180 cm  [#permalink]

Show Tags

New post 02 Aug 2018, 03:35
MathRevolution wrote:
[Math Revolution GMAT math practice question]

If the average (arithmetic mean) height of Bob, John and Tom is 180 cm, what is their median height?

1) Bob’s height is 175cm.
2) John’s height is 180cm.


1) Bob’s height is 175cm.
it means that Bob is either the median or the least !!

insufficient

2) John’s height is 180cm
In this case John cannot be highest or lowest
given J= 180
B+T=360
even if B/T =179.9 (highest value) , T/B >180

which leaves us with
1.all of them are 180 cm - in this case median = 180
2.John's height =180 - median = 180

sufficient
Math Revolution GMAT Instructor
User avatar
V
Joined: 16 Aug 2015
Posts: 6020
GMAT 1: 760 Q51 V42
GPA: 3.82
Premium Member
Re: If the average (arithmetic mean) height of Bob, John and Tom is 180 cm  [#permalink]

Show Tags

New post 05 Aug 2018, 19:02
=>

Forget conventional ways of solving math questions. For DS problems, the VA (Variable Approach) method is the quickest and easiest way to find the answer without actually solving the problem. Remember that equal numbers of variables and independent equations ensure a solution.

The first step of the VA (Variable Approach) method is to modify the original condition and the question. We then recheck the question.

When we have 3 numbers, if one of them is equal to their average, then it is also equal to their median.

Thus, condition 2) is sufficient.

Therefore, B is the answer.
Answer: B
_________________

MathRevolution: Finish GMAT Quant Section with 10 minutes to spare
The one-and-only World’s First Variable Approach for DS and IVY Approach for PS with ease, speed and accuracy.
"Only $99 for 3 month Online Course"
"Free Resources-30 day online access & Diagnostic Test"
"Unlimited Access to over 120 free video lessons - try it yourself"

Re: If the average (arithmetic mean) height of Bob, John and Tom is 180 cm &nbs [#permalink] 05 Aug 2018, 19:02
Display posts from previous: Sort by

If the average (arithmetic mean) height of Bob, John and Tom is 180 cm

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

Events & Promotions

PREV
NEXT


GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

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

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.