Which of the following could be the median of a set consisti : Problem Solving (PS)

ipsprabhu

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Re: Please solve this [#permalink]

23 Feb 2010, 04:44

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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.

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Re: Can you please explain this !!!!! [#permalink]

30 Mar 2010, 22:20

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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!!!!!

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Re: Can you please explain this !!!!! [#permalink]

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

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Re: Can you please explain this !!!!! [#permalink]

05 Oct 2010, 04:22

Please post the official explaination E seems to be ambiguis as 39 is not average of any two primes

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Bunuel

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Re: Can you please explain this !!!!! [#permalink]

05 Oct 2010, 04:41

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prashantbacchewar wrote:

Please post the official explaination E seems to be ambiguis as 39 is not average of any two primes

Actually it is: 37 and 41 --> average = 39.

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Re: Which of the following could be the median [#permalink]

14 Aug 2013, 03:37

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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.

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Re: Which of the following could be the median of a set consisti [#permalink]

19 Apr 2014, 23:47

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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)

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Re: Which of the following could be the median of a set consisti [#permalink]

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.

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Which of the following could be the median of a set consisti [#permalink]

07 Aug 2020, 03:40

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The median of 6 numbers will be the average of the 3rd and 4th Number.
Prime numbers start with 2 hence option a & b are ruled out
for option c to be valid the sum of 3rd and 4th prime number should be 21 (2 and 19 are the only primes to sum to21)
for option d to be valid the sum of 3rd and 4th prime number should be 25 (2 and 23 are the only primes to sum to23)
Option E is left and that is the correct answer

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Which of the following could be the median of a set consisti [#permalink]

21 Aug 2020, 21:03

Rule: 2 is the only Even Prime No. - every other Prime No. is a (+)Positive ODD Integer.

A set consisting of 6 Different Prime Numbers placed in Ascending Order will have the Middle 2 Values both = ODD

Rule: in a Set consisting of an EVEN COUNT of Terms, the Median can be found by taking the 2 Middle Terms (here the 3rd Term and 4th Term) and finding the MEAN

(Odd Prime + Odd Prime) / 2 = Even /2 = Integer Median

Eliminate C and D

Since A (2) is the 1st Prime No. and B (3) is the 2nd Prime No. they can NEVER be the Median in a Set of 6 Distinct Prime Nos.

E - 39

2 Middle Prime Nos. in the Set = 37 and 41

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Re: Which of the following could be the median of a set consisti [#permalink]

10 Sep 2020, 09:47

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!!!!!

3 is a prime number ! however the way you have calculated the answer is correct

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TerryWill700

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Re: Which of the following could be the median of a set consisti [#permalink]

12 Apr 2023, 08:03

Is this question an official question? It didnt mention anything about sequence of these prime numbers, from smallest value to the biggest value
Maybe these prime numbers just place randomly so the median can include 2
Did I miss anything important? plz Bunuel chetan2u

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Bunuel

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Re: Which of the following could be the median of a set consisti [#permalink]

12 Apr 2023, 08:29

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TerryWill700 wrote:

Is this question an official question? It didnt mention anything about sequence of these prime numbers, from smallest value to the biggest value
Maybe these prime numbers just place randomly so the median can include 2
Did I miss anything important? plz Bunuel chetan2u

For a set with an odd number of elements, the median is the middle value when the elements are arranged in ascending or descending order.

For a set with an even number of elements, the median is the average of the two middle values when the elements are arranged in ascending or descending order.

Therefore, the median is defined for a set which is already arranged in ascending or descending order.

Hope it helps.

P.S. This is not an official question.

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TerryWill700

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Re: Which of the following could be the median of a set consisti [#permalink]

12 Apr 2023, 10:32

Thx Bunuel!!!
My bad I forgot basic concept of median (not allowed in GMAT quant)
Takeaway: Even if the question did not provide any info about ascending or descending order
But median itself means ascending or descending order!
As the definition of median is: " The middle number; found by ordering all data points and picking out the one in the middle (or if there are two middle numbers, taking the mean of those two numbers)"

gmatclubot

Re: Which of the following could be the median of a set consisti [#permalink]

12 Apr 2023, 10:32

GMAT Problem Solving (PS) Questions

Which of the following could be the median of a set consisti