Get detailed explanations to advanced GMAT questions.

If Sn is the sum of the first n terms of a certain sequence and if Sn = n(n+1) for all positive integers n, what is the third term of the sequence?

Option A:

3

Option B:

4

Option C:

6

Option D:

8

Option E:

9

Option C is the correct answer.

Let there be 3 terms in the sequence, namely a, b & c

Given that a + b + c = 3 * 4 = 12………….. (1)

Now say there are 2 terms, namely a & b

So, a + b = 2 * 3 = 6………. (2)

Substitute value of a+b from eqn (2) in eqn (1)

6 + c = 12

c = 6

- A grocery store purchased crates of 40 oranges each for $5.00 per crate and then sold each orange for $0.20. What was the store’s gross profit on each crate of oranges?

- At a certain committee meeting only associate professors and assistant professors are present…

- If v = √(2(9.8))m/0.5j), m = 96, and j = 49,which of the following most closely approximates the value of v?

- On May 1 of last year, Jasmin invested x dollars in a new account at an interest rate of 6 percent per…

- (1+0.0001)/(0.04+10) The value of the expression above is closest to which of the following?

- Copyright © 2020. All Rights Reserved. Crafted by Pixelmattic