GMAT Problem Solving (PS) | Re: A set S consists of the integers {1, 2, 3, 4 . . . (2n + 1)}, where n

Given data :
Set S : {1, 2, 3, 4 . . . (2n + 1)}
n is a positive number, X the average of odd numbers and Y the average of even number
We have been asked to find out what is the value of X-Y.

2n + 1 is definitely going to be odd(both if x is odd or even)
If n=3, 2n+1 = 7 (odd)
If n=2, 2n+1 = 5 (odd)

If n is 2, the last element in the set is 5.
The number of odd integers are 3 and numbers of even integers are 2.

The average of 3 odd numbers =\( \frac{(1+3+5)}{3} \)
...

---