GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 16 Jan 2019, 20:50

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

## Events & Promotions

###### Events & Promotions in January
PrevNext
SuMoTuWeThFrSa
303112345
6789101112
13141516171819
20212223242526
272829303112
Open Detailed Calendar
• ### The winning strategy for a high GRE score

January 17, 2019

January 17, 2019

08:00 AM PST

09:00 AM PST

Learn the winning strategy for a high GRE score — what do people who reach a high score do differently? We're going to share insights, tips and strategies from data we've collected from over 50,000 students who used examPAL.
• ### Free GMAT Strategy Webinar

January 19, 2019

January 19, 2019

07:00 AM PST

09:00 AM PST

Aiming to score 760+? Attend this FREE session to learn how to Define your GMAT Strategy, Create your Study Plan and Master the Core Skills to excel on the GMAT.

# What is the 1st term in sequence S ?

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:

### Hide Tags

Senior DS Moderator
Joined: 27 Oct 2017
Posts: 1195
Location: India
Concentration: International Business, General Management
GPA: 3.64
WE: Business Development (Energy and Utilities)
What is the 1st term in sequence S ?  [#permalink]

### Show Tags

06 Nov 2018, 08:47
2
00:00

Difficulty:

5% (low)

Question Stats:

84% (00:36) correct 16% (00:43) wrong based on 187 sessions

### HideShow timer Statistics

Project DS Butler: Day 1: Data Sufficiency (DS1)

What is the 1st term in sequence S ?
(1) The 3rd term in S is 2.
(2) The 2nd term in S is twice the 1st, and the 3rd term is three times the 2nd.

The best/excellent answers get kudos.

_________________
Director
Joined: 18 Jul 2018
Posts: 557
Location: India
Concentration: Finance, Marketing
WE: Engineering (Energy and Utilities)
Re: What is the 1st term in sequence S ?  [#permalink]

### Show Tags

06 Nov 2018, 09:28
1
1
1
Question stem. What's the value of $$S_1$$ ?

From statement 1:

$$S_3 = 2$$.
Clearly Insufficient.

From statement 2:

$$S_2 = 2S_1$$
$$S_3 = 3S_2$$
All 3 unknows.
Insufficient.

Combining both:

$$S_3 = 2$$
Then $$S_2$$ = 1.
So, $$S_1$$ = 1/2.

C is the answer.
_________________

If you are not badly hurt, you don't learn. If you don't learn, you don't grow. If you don't grow, you don't live. If you don't live, you don't know your worth. If you don't know your worth, then what's the point?

RC Moderator
Joined: 24 Aug 2016
Posts: 632
Concentration: Entrepreneurship, Operations
GMAT 1: 630 Q48 V28
GMAT 2: 540 Q49 V16
Re: What is the 1st term in sequence S ?  [#permalink]

### Show Tags

06 Nov 2018, 09:45
1
(1) The 3rd term in S is 2. - NS: S3 =2
(2) The 2nd term in S is twice the 1st, and the 3rd term is three times the 2nd. -NS : ==> S3 =3S2 =6S1
(1+2) Sufficient : as S3 =2 , Hence, S1 = $$\frac{2}{6} = \frac{1}{3}$$ ..... Hence Ans C
_________________

Please let me know if I am going in wrong direction.
Thanks in appreciation.

Manager
Joined: 09 Jun 2018
Posts: 184
Location: United States
GPA: 3.95
WE: Manufacturing and Production (Energy and Utilities)
Re: What is the 1st term in sequence S ?  [#permalink]

### Show Tags

06 Nov 2018, 10:03
1
No need to solve completely as this is a DS question!

Stmt 1: S3 = 2, No info on S1, Insufficient. Eliminate A,D
Stmt 2: S2 = 2*S1, S3 = 3*S2, No values given for any term, so cannot find out value of S1, Insufficient. Eliminate B

Combined: We can find the value of S1, by back tracking through the three equations from Stmts 1 and 2. Hence Sufficient.

Option C
_________________

If you found this relevant and useful, please Smash that Kudos button!

Director
Joined: 19 Oct 2013
Posts: 509
Location: Kuwait
GPA: 3.2
WE: Engineering (Real Estate)
Re: What is the 1st term in sequence S ?  [#permalink]

### Show Tags

08 Nov 2018, 06:11
Given that $$S_3 = 2$$. We cannot figure any specific value for S1

Insufficient.

We look at Statement 2) it tells us$$S_2 = 2*S_1$$ and $$S_3 = 3*S_2$$.

Still insufficient as I have 2 equations and 3 variables.

Combining both we have one variable that can be substituted to provide a numerical value. This numerical value can then be substituted in the other equation.

C
Manager
Joined: 05 Jul 2018
Posts: 56
Location: India
Concentration: General Management, Technology
GRE 1: Q162 V149
GPA: 3.6
WE: Information Technology (Consulting)
What is the 1st term in sequence S ?  [#permalink]

### Show Tags

09 Nov 2018, 21:25
1
gmatbusters wrote:

Project DS Butler: Day 1: Data Sufficiency (DS1)

What is the 1st term in sequence S ?
(1) The 3rd term in S is 2.
(2) The 2nd term in S is twice the 1st, and the 3rd term is three times the 2nd.

The best/excellent answers get kudos.

Statement 1 This only gives us the value of 3rd term and no relation whatsoever to the 1st term of the sequence. There is no way we can find the first term of the sequence using this info. Hence, this is INSUFFICIENT

Statement 2 This gives us relation about the 3 terms. Now we know the first 3 terms will look somewhat like this--> a, 2a, 6a. But we have no clue about the value of 'a' here. Hence, this alone is INSUFFICIENT

Statement 1 + Statement 2 Now we know that 6a=2. Hence we can find the value of a which is 1/3. hence we get a unique numerical value. hence this is SUFFICIENT

Hence, the answer is C

_________________

Appreciate any KUDOS given !
MY MBA RESOURCES:

CEO
Joined: 11 Sep 2015
Posts: 3326
Re: What is the 1st term in sequence S ?  [#permalink]

### Show Tags

31 Dec 2018, 09:52
Top Contributor
gmatbusters wrote:

Project DS Butler: Day 1: Data Sufficiency (DS1)

What is the 1st term in sequence S ?
(1) The 3rd term in S is 2.
(2) The 2nd term in S is twice the 1st, and the 3rd term is three times the 2nd.

Target question: What is the 1st term in sequence S ?

Statement 1: The 3rd term in S is 2
Since we're not given any information about the NATURE of the sequence, there's no way to answer the target question with certainty.
So, statement 1 is NOT SUFFICIENT

Statement 2: The 2nd term in S is twice the 1st, and the 3rd term is three times the 2nd.
Great, we're given information about the NATURE of the sequence, but we aren't given the VALUE of any terms.
For example, consider these two possible cases that satisfy statement 2:
Case a: The first 3 terms are: {1, 2, 6....}. In this case, the answer to the target question is the 1st term is 1
Case b: The first 3 terms are: {3, 6, 18....}. In this case, the answer to the target question is the 1st term is 3
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
Statement 1 tells us that the 3rd term in S is 2
Statement 2 tells us that the 3rd term is three times the 2nd. So, if the 3rd term is 2, then the 2nd term must be 2/3
Statement 2 also tells us that the 2nd term in S is twice the 1st. So, if the 2nd term is 2/3, then the 1st term must be 1/3
Since we can answer the target question with certainty, the combined statements are SUFFICIENT

Cheers,
Brent
_________________

Test confidently with gmatprepnow.com

Intern
Joined: 17 Dec 2018
Posts: 8
Re: What is the 1st term in sequence S ?  [#permalink]

### Show Tags

02 Jan 2019, 01:48
gmatbusters wrote:

Project DS Butler: Day 1: Data Sufficiency (DS1)

What is the 1st term in sequence S ?
(1) The 3rd term in S is 2.
(2) The 2nd term in S is twice the 1st, and the 3rd term is three times the 2nd.

The best/excellent answers get kudos.

Hello gmatbusters,

in the question is not said, that there are only 3 terms.
Do I have to assume so?

I thought it would be E because there was no information about the total number of terms
Director
Joined: 18 Jul 2018
Posts: 557
Location: India
Concentration: Finance, Marketing
WE: Engineering (Energy and Utilities)
Re: What is the 1st term in sequence S ?  [#permalink]

### Show Tags

02 Jan 2019, 05:29
1
gzuz wrote:
gmatbusters wrote:

Project DS Butler: Day 1: Data Sufficiency (DS1)

What is the 1st term in sequence S ?
(1) The 3rd term in S is 2.
(2) The 2nd term in S is twice the 1st, and the 3rd term is three times the 2nd.

The best/excellent answers get kudos.

Hello gmatbusters,

in the question is not said, that there are only 3 terms.
Do I have to assume so?

I thought it would be E because there was no information about the total number of terms

Hey gzuz, Let me try to answer.
The minimum number of terms you need to determine the kind of series (AP, GP or HP).
Hence when 2 statements are combined, we are able the find the first term.
Hence C is the answer.
_________________

If you are not badly hurt, you don't learn. If you don't learn, you don't grow. If you don't grow, you don't live. If you don't live, you don't know your worth. If you don't know your worth, then what's the point?

CEO
Joined: 11 Sep 2015
Posts: 3326
Re: What is the 1st term in sequence S ?  [#permalink]

### Show Tags

02 Jan 2019, 05:43
1
Top Contributor
gzuz wrote:
Hello gmatbusters,

in the question is not said, that there are only 3 terms.
Do I have to assume so?

I thought it would be E because there was no information about the total number of terms

The target question only asks us to determine "the 1st term in sequence S"
So, the total number of terms in the sequence has no bearing on our ability to answer the target question.

Cheers,
Brent
_________________

Test confidently with gmatprepnow.com

Re: What is the 1st term in sequence S ? &nbs [#permalink] 02 Jan 2019, 05:43
Display posts from previous: Sort by

# What is the 1st term in sequence S ?

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.