What is the thousandth term of S, a certain sequence of numbers?
(1) For every n, the nth term of S is n^2.
(2) The first five terms of S are 1^2, 2^2, 3^2, 4^2, and 5^2.
OA A
Source: GMAT Prep
5-Day Free Trial
5-day free, full-access trial TTP
Available with Beat the GMAT members only code
MORE DETAILS
What is the thousandth term of S, a certain sequence of numbers? (1) For every n, the nth term of S is n^2.
This topic has expert replies
-
BTGmoderatorDC
- Moderator
- Posts: 7187
- Joined: Thu Sep 07, 2017 4:43 pm
- Followed by:23 members
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
GMAT/MBA Expert
-
Brent@GMATPrepNow
- GMAT Instructor
- Posts: 16207
- Joined: Mon Dec 08, 2008 6:26 pm
- Location: Vancouver, BC
- Thanked: 5254 times
- Followed by:1268 members
- GMAT Score:770
Timer
00:00
Your Answer
A
B
C
D
E
Global Stats
Target question: What is the value of term_1000?BTGmoderatorDC wrote: ↑Mon Mar 20, 2023 2:11 pmWhat is the thousandth term of S, a certain sequence of numbers?
(1) For every n, the nth term of S is n^2.
(2) The first five terms of S are 1^2, 2^2, 3^2, 4^2, and 5^2.
OA A
Source: GMAT Prep
Statement 1: For every n, the nth term of S is n².
Perfect! Statement 1 provides a "recipe" for determining the value of ANY term in the sequence.
So, it must be the case that term_1000 = 1000² = 1,000,000
Since we can answer the target question with certainty, statement 1 is SUFFICIENT
Statement 2: The first five terms of S are 1², 2², 3², 4², and 5².
Important: Even though it certainly LOOKS like there is a pattern here, we can't assume that it continues,
For example, the sequence COULD just be a list of someone's favorite numbers.
So, it COULD be the case that term_6 = 17², term_7 = 5.3, term_8 = -9.22, etc, in which case, term_1000 can have pretty much any value
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT
Answer: A
Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
