Author 
Message 
TAGS:

Hide Tags

Intern
Joined: 29 Nov 2009
Posts: 26
Location: Bangalore  INDIA
Schools: Duke, NUS,Rutgers
WE 1: Health & Life Science

Which of the following could be the median of a set consisti
[#permalink]
Show Tags
Updated on: 06 Sep 2013, 07:14
Question Stats:
69% (01:08) correct 31% (01:00) wrong based on 838 sessions
HideShow timer Statistics
Which of the following could be the median of a set consisting of 6 different primes? A. 2 B. 3 C. 9.5 D. 12.5 E. 39 The answer is E, however can any one please explain this problem for me. Why it is 39:?:
Official Answer and Stats are available only to registered users. Register/ Login.
Originally posted by divakarbio7 on 22 Feb 2010, 22:48.
Last edited by Narenn on 06 Sep 2013, 07:14, edited 1 time in total.
Always put OA in the spoiler.




Manager
Joined: 26 May 2005
Posts: 193

Re: Please solve this
[#permalink]
Show Tags
22 Feb 2010, 23:45
median of a set containing 6 different primes median will be average of 3rd and 4th prime. All prime greater than 2 are odd. So 3th and 4th primes are odd and their sum will be even and the median will be an integer. 3rd prime will be greater than 2 or 3(first 2 primes)
E




Intern
Joined: 29 Nov 2009
Posts: 26
Location: Bangalore  INDIA
Schools: Duke, NUS,Rutgers
WE 1: Health & Life Science

Re: Please solve this
[#permalink]
Show Tags
22 Feb 2010, 23:53
Thanks for the reply.
Had an another doubt, say if the answer choice had "40" as one of the option. Then the answer 39 makes sense? ( Why I am confused is as per the rule stated, sum of the odd numbers is even, however 39 is not even).. Correct me if I am wrong
Thanks Again Divakar KN



Intern
Joined: 10 Dec 2009
Posts: 1

Re: Please solve this
[#permalink]
Show Tags
23 Feb 2010, 04:44
divakarbio7 wrote: Thanks for the reply.
Had an another doubt, say if the answer choice had "40" as one of the option. Then the answer 39 makes sense? ( Why I am confused is as per the rule stated, sum of the odd numbers is even, however 39 is not even).. Correct me if I am wrong
Thanks Again Divakar KN The median is calculated as the average of the two middle numbers. If the sum of the two numbers is even, average of those numbers can be even or odd. In this case the median is an odd number. Hence 39.



Manager
Joined: 26 May 2005
Posts: 193

Re: Please solve this
[#permalink]
Show Tags
23 Feb 2010, 09:16
divakarbio7 wrote: Thanks for the reply.
Had an another doubt, say if the answer choice had "40" as one of the option. Then the answer 39 makes sense? ( Why I am confused is as per the rule stated, sum of the odd numbers is even, however 39 is not even).. Correct me if I am wrong
Thanks Again Divakar KN median is average of the middle 2 numbers(if the number of the items is even). sum of even, so the median will definitely be integer. if another choice is 40, then i belive we got to pick up the numbers to see which one is the correct median.



Manager
Joined: 01 Feb 2010
Posts: 239

Re: Please solve this
[#permalink]
Show Tags
23 Feb 2010, 21:59
divakarbio7 wrote: Thanks for the reply.
Had an another doubt, say if the answer choice had "40" as one of the option. Then the answer 39 makes sense? ( Why I am confused is as per the rule stated, sum of the odd numbers is even, however 39 is not even).. Correct me if I am wrong
Thanks Again Divakar KN odd+odd is even and even divided by 2 is always an integer. Also it can't be 2 or 3 as all primes numbers are different. Hence best possible choices is 39.



Intern
Joined: 29 Nov 2009
Posts: 26
Location: Bangalore  INDIA
Schools: Duke, NUS,Rutgers
WE 1: Health & Life Science

Can you please explain this !!!!!
[#permalink]
Show Tags
30 Mar 2010, 22:13
Which of the following could be the median of a set consisting of 6 different primes? A> 2 B> 3 C> 9.5 D> 12.5 E> 39 Answer says 39, however i am unable to understand this....



Intern
Joined: 29 Nov 2009
Posts: 26
Location: Bangalore  INDIA
Schools: Duke, NUS,Rutgers
WE 1: Health & Life Science

Re: Can you please explain this !!!!!
[#permalink]
Show Tags
30 Mar 2010, 22:20
Is this the correct Reasoning?
A> 2  first prime, hence cant be a median B> 3  this option is out, because 3 is not a prime number Option C & D  9.5 & 12.5  cant be the median because in 6 different prime the average for median shouldnt be a decimal (odd+ odd = even) so these options are out
E> 39  only option left out is this  so it should be the answer!!!!!



Manager
Joined: 01 Feb 2010
Posts: 239

Re: Can you please explain this !!!!!
[#permalink]
Show Tags
30 Mar 2010, 22:34
divakarbio7 wrote: Is this the correct Reasoning?
A> 2  first prime, hence cant be a median B> 3  this option is out, because 3 is not a prime number Option C & D  9.5 & 12.5  cant be the median because in 6 different prime the average for median shouldnt be a decimal (odd+ odd = even) so these options are out
E> 39  only option left out is this  so it should be the answer!!!!! Approach is correct. Some modification to your explanation: A: 2  first prime, hence cant be a median B: 3  Second prime, hence cant be a median C & D: 9.5 & 12.5  cannot be the median because in case of 6 different prime the average of two odd numbers cannot be decimal. E: 39  only option left out is this  so it should be the answer



Intern
Joined: 29 Nov 2009
Posts: 26
Location: Bangalore  INDIA
Schools: Duke, NUS,Rutgers
WE 1: Health & Life Science

Re: Can you please explain this !!!!!
[#permalink]
Show Tags
01 Apr 2010, 05:59
Hi ,
Thank you for the explanation.
Have 2 more questions: what is the value of n in the list k, n, 12, 6, 17? a> k< n b> The median of the numbers in the list is 10
What is the median number of employees per project for the projects at company Z? a> 25 percent of the projects at company Z have 4 or more employees assigned to each project b> 35 percent of the projects at company Z have 2 or fewer employees assigned to each project.
i am not able to understand the logic for 2nd problem..answer says C  but note sure why?



Manager
Joined: 20 Apr 2010
Posts: 185
Schools: ISB, HEC, Said

Re: Can you please explain this !!!!!
[#permalink]
Show Tags
05 Oct 2010, 04:22
Please post the official explaination E seems to be ambiguis as 39 is not average of any two primes



Math Expert
Joined: 02 Sep 2009
Posts: 47898

Re: Can you please explain this !!!!!
[#permalink]
Show Tags
05 Oct 2010, 04:41



Intern
Joined: 16 Jan 2013
Posts: 28
Concentration: Finance, Entrepreneurship
GMAT Date: 08252013

Which of the following could be the median
[#permalink]
Show Tags
14 Aug 2013, 03:33
Which of the following could be the median of a set consisting of 6 different primes? (A) 2 (B) 3 (C) 9.5 (D) 12.5 (E) 39
Can somebody plz explain how to proceed.
Thanks in advance.



Verbal Forum Moderator
Joined: 10 Oct 2012
Posts: 615

Re: Which of the following could be the median
[#permalink]
Show Tags
14 Aug 2013, 03:37
Countdown wrote: Which of the following could be the median of a set consisting of 6 different primes? (A) 2 (B) 3 (C) 9.5 (D) 12.5 (E) 39
Can somebody plz explain how to proceed.
Thanks in advance. Median of 6 primes :\(\frac{odd+odd}{2}\) = Integer. Options C and D are discarded immediately. Options A and B can never be the median of 6 primes. Only option E remains.
_________________
All that is equal and notDeep Dive Inequality
Hit and Trial for Integral Solutions



Math Expert
Joined: 02 Sep 2009
Posts: 47898

Re: Which of the following could be the median
[#permalink]
Show Tags
14 Aug 2013, 03:43



Director
Joined: 03 Aug 2012
Posts: 822
Concentration: General Management, General Management
GMAT 1: 630 Q47 V29 GMAT 2: 680 Q50 V32
GPA: 3.7
WE: Information Technology (Investment Banking)

Re: Which of the following could be the median of a set consisti
[#permalink]
Show Tags
19 Apr 2014, 23:47
This can be done by hit and trial. (A) 2 (B) 3 (C) 9.5 (D) 12.5 (E) 39 Since all primes should be different, we can take one set as below: 2..3..5..7..11..13 Median (5+7)/2 = 6 Hence, median cannot be less than 6, so reject options A and B Since primes are odd and the number of terms is 6. So, we will always have median in the below form (odd+odd)/2 = Even/2 = Integer. Reject (C) and (D) Hence (E)
_________________
Rgds, TGC! _____________________________________________________________________ I Assisted You => KUDOS Please _____________________________________________________________________________



Director
Joined: 05 Mar 2015
Posts: 985

Re: Which of the following could be the median of a set consisti
[#permalink]
Show Tags
22 Dec 2015, 12:37
Countdown wrote: Which of the following could be the median of a set consisting of 6 different primes? (A) 2 (B) 3 (C) 9.5 (D) 12.5 (E) 39
Can somebody plz explain how to proceed.
Thanks in advance. let the consecutive primes be a,b,c,d,e,f So the median will be (c+d)/2 Looking options we have to find 2*(any options) as sum of two consecutive primes. becoz median here is avg. of two primes. 1) 2 (ie 2*2=4) so 4 cannot be the sum of middle two primes in a set of six consecutive primes. 2) 3 (3*2=6) same as option 1. 3)9.5(2*9.5=19) so sum can be 17+2 but 17 and 2 were not consecutive. 4)12.5 (2*12.5=25) same as option 3 ie we cannot find any two consecutive primes adding to 25. 5)39 (2*39=78) so here we find 78=37+41 are the two consecutive primes so the set is{29,31,37,41,43,47} so E is our ans.



Senior Manager
Joined: 15 Jan 2017
Posts: 367

Re: Which of the following could be the median of a set consisti
[#permalink]
Show Tags
10 Dec 2017, 11:00
Based on options 2,3 are out. 9.5 and 12.5 means odd numbers are divided by two . 19/2 and 25/2. Both of them have only even numbers as its break up, so have to discard it (after 2 no other even number is prime). leaves us with 39 which is possible (by the break two odd number 7 + 2) so chose that. Kudos if my explanation made sense to you




Re: Which of the following could be the median of a set consisti &nbs
[#permalink]
10 Dec 2017, 11:00






