vaivish wrote:If Xn =n^2+8n+20 for n=7, 4, 8, 5, 10, 11, 6, 12, and 9, what is the median of all Xn?
A. 68
B. 104
C. 125
D. 144
E. 148

Since all the terms in the expression are positive, the bigger the value of n, the bigger the value of the expression.

If we want the median value of the expression, we merely need to find the median value of n and plug in. As with most properties of sets questions, let's start by arranging the set in ascending order:

n = {4, 5, 6, 7, 8, 9, 10, 11, 12}

We have an odd number of terms, so the median term is the one in the middle. Therefore, we use n=8.

So, if n=8:

8^2 + 8(8) + 20 = 64 + 64 + 20 = 148... choose (E).