M70-29

Question

Set A consists of  n  consecutive integers, denoted from  Q_1  to  Q_n . What is the median of Set A?

(1)  \frac{Q_1+Q_2+Q_3+...+Q_n}{n}=13 
 
(2)  Q_1=7  and  Q_n=19

Bunuel · Answer

Official Solution:

We’ll go for LOGICAL because we can use the logic of median and average.
 
In a set of consecutive integers, the average and the median are the same. Therefore, (1) is sufficient to give us the median. (B), (C) and (E) are eliminated. 
 
(2) is also sufficient on its own, as we know that the set of consecutive integers goes from 7 to 19: if we know all the numbers in set A, that’s enough in order to find its median. (A) is also eliminated.

Answer: D

vando · Answer

I dont understand s1, we dont have the value of n, so how can u solve it? Pls clarify this more.

rishab0507 · Answer

It doesn't matter if you have value of n or not, what matter is rule, 
In a set of consecutive integers, the average and the median are the same.

you can check it for some no.'s and see

ltkngoc222 · Answer

Sorry but I think it's not always be the case that the average and the median are the same for a set of consecutive integers. This is true only when there is an odd number of items in the data set. For data set with even number of items, the media is the average of the two most middle numbers.

Bunuel · Answer

{2, 3, 4, 5}

Median = (3 + 4)/2 = 3.5
Average = (2 + 3 + 4 + 5)/4 = 3.5.

For evenly spaced set, median always equals to the mean (average).

ltkngoc222 · Answer

Oh I see, thanks so much!

M70-29

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards