Data Sufficiency

Is it D?

There are multiple ways you can solve this.

Approach 1:

avg of first nine int = 7
So, sum = 63
n/2 [ 2a + (n-1)d ] = 63
You can find 'a' and hence you can find the avg
Using (1) or (2), you can find the average

Approach 2:

For consecutive numbers, if there are an odd number of numbers in
the sequence, then mean = median

So, if your sequence is below, then you are basically looking for
the mean "a6"

a1 a2 a3 a4 a5 a6 a7 a8 a9 a10 a11

(1) tells you that a5 = 7, so you know what a6 is

(2) same approach. you can find a6

Can someone (preferably an expert) tells us what is the answer here?

D is right. look up here https://gmat-maths.blocked/2008/01/ ... ng-41.html