GMatPrep : Median

[catchkedar]

Please find attacment

[jay711]

I saw this question today, don't remember on the computer test or book.

 

 

(1)

- try 3,5,7,9 -> then mean=median=6

- 11,13,15,17,19 -> then mean=median=15

- 10,12,14,16,18 -> then mean=median=14

suff

 

(2) Then range of set is 2(n-1) - this only give you how much different of the smallest number from the biggest number, it doesn't give you any info about the other members in between

 

for example if n=5, then 2(5-1) = 8

 

let try, the smallest is 3 then biggest is 11, the other 3 members in between

 

3,4,6,6,11 - then mean = median = 6

3,8,9,10,11 - then mean (8.2) median (9)

- insuff

 

 

[catchkedar]

so it means that median of 4 numbers is (2nd +3rd)/2.............

i was confused about that only......

[charu_mulye]

concur with jay on this one..

[kk_del]

You can do it by considering AP

 

 

x , x+2 , X+4 ...x+2(n-1)

 

Sum / n = x+n-1 = AM

 

Try putting values now ...

 

A is suff

[vedigaurav]

I got this correct on GMAtPREP. :)

Answer is indeed A.

 

STMT 1:

Pick n = 4 and 5.

When N= 4, let the set be {2,4,6,8} - Mean and median are equal.

When N=5, Let teh set be {3,5,7,9,11} - Mean and median are equal.

 

Sufficient.

 

STMT 2:

Insufficient. range is of no use here.

[bug]

agreed, it's A.

with stmt 2: we can only say that the max-min=8 so, but the numbers in between max and min can be equal to one another, consecutive,or anything, we don't know. hence insufficient.

[Gmater-1]

Stmt1: esentially means that numbers are consecutive with difference of 2 and for any consecutive number sequence median = mean

 

Stmt 2 : doesn't help, range is of no importance

[gmat009]

Problem comes up when you have to prove stmt 2 is insufficient.

Range gives no idea but to prove it insufficient we have to find Yes and No.

Yes- Values which make mean equal median

NO- Values that make Mean not equal to median.

I was having hard time to find values in which mean is equal to median and satisfy 2(n-1) in less than 2 minutes.