BTGModeratorVI wrote: ↑

Mon Sep 14, 2020 8:41 am

If a sequence of 8 consecutive odd integers with increasing values has 9 as its 7th term, what is the sum of the terms of the sequence?

(A) 22
(B) 32
(C) 36
(D) 40
(E) 44

Answer: B
Source: Official guide

One way to solve is to use the following rule that says, "In a set where the numbers are equally spaced, the mean will equal the median."
For example, in each of the following sets, the mean and median are equal:
{7, 9, 11, 13, 15}
{-1, 4, 9, 14}
{3, 4, 5, 6}

Since we the 8 consecutive odd integers are equally spaced, the median = the mean
The median of the 8 terms will be the average of term4 and term5.

Given: term7 = 9
So, term6 = 7
term5 = 5
term4 = 3

So, the median of the 8 terms = (5 + 3)/2 = 4
So, the MEAN of the 8 terms is also 4

If the mean of the 8 terms = 4, then the SUM of the 8 terms = (8)(4) = 32
Answer: B

Cheers,
Brent