GMAT Prep 2 Question

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GMAT Prep 2 Question

by Nole23 » Thu Jun 25, 2009 7:00 pm
For the set of N numbers where N > 1, is the average equal to the median?

A. N is listed in increasing order, then the difference between any pair of successive numbers is 2.

B. The range of N numbers in the set is 2(N-1)

OA:A

I understand the concept that in consecutive equally spaced numbers median is equal to mean, but I am not sure why B is wrong.
Source: — Data Sufficiency |

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by shanmugam.d » Thu Jun 25, 2009 10:41 pm
You have to apply the principle of consecutive nos: i.e for any sets having consecutive no's (be it simple consecutive no. or consecutive odd or consecutive even) the mean and median are always equal.

from (1) you can identify that the set is of consecutive no's. but from (2) you can only tell the last and first digit are even.

Hence the answer is A

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hope this helps

by deltaforce » Fri Jun 26, 2009 3:46 am
basically plug in values for the second and see

2(n-1) plug n = 20
and u get range as 20- 2 = 18

nos can be consecutive, even, random....

sometime best thing to do is plug in nos and see