Find all School-related info fast with the new School-Specific MBA Forum

It is currently 21 Jul 2014, 23:29

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

In the sequence of non-zero numbers t1, t2,t3,......tn,.....

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
avatar
Joined: 19 May 2008
Posts: 18
Followers: 0

Kudos [?]: 0 [0], given: 0

In the sequence of non-zero numbers t1, t2,t3,......tn,..... [#permalink] New post 12 Jul 2008, 21:34
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

60% (02:07) correct 40% (01:21) wrong based on 44 sessions
In the sequence of non-zero numbers t1, t2,t3,......tn,.....,tn+1 =tn/2 for all positive integers of n. What is the value of t5?

(1) t3 = 1/4
(2) t1 - t5 = 15/16

OPEN DISCUSSION OF THIS QUESTION IS HERE: in-the-sequence-1-2-4-8-16-32-each-term-after-the-104175.html
[Reveal] Spoiler: OA
Kaplan Promo CodeKnewton GMAT Discount CodesGMAT Pill GMAT Discount Codes
CEO
CEO
User avatar
Joined: 29 Aug 2007
Posts: 2501
Followers: 51

Kudos [?]: 482 [0], given: 19

GMAT Tests User
Re: DS Sequence [#permalink] New post 12 Jul 2008, 22:02
riks200 wrote:
In the sequence of non-zero numbers t1, t2,t3,......tn,.....,tn+1 =t2/2 for all positive integers of n. What is the value of t5?
1. t3=1/4
2. t1-t5=15/16

Pls Explain?


is the question a complete one? seems the question is not complete for me.

what is equal to t2/2?
_________________

Verbal: new-to-the-verbal-forum-please-read-this-first-77546.html
Math: new-to-the-math-forum-please-read-this-first-77764.html
Gmat: everything-you-need-to-prepare-for-the-gmat-revised-77983.html


GT

Director
Director
avatar
Joined: 27 May 2008
Posts: 552
Followers: 5

Kudos [?]: 161 [0], given: 0

GMAT Tests User
Re: DS Sequence [#permalink] New post 12 Jul 2008, 22:51
there is a typo in the question, refer 7-t66979
Intern
Intern
avatar
Joined: 24 Jul 2013
Posts: 1
Followers: 0

Kudos [?]: 0 [0], given: 0

Re: In the sequence of non-zero numbers t1, [#permalink] New post 23 Aug 2013, 02:14
correction: tn+1 =tn/2

1) SUFFICIENT: t3=1/4 hence t4=1/4/2=1/8 and t5=1/8/2=1/16
2) SUFFICIENT: t1-(t1/2/2/2/2)=15/16 -> t1-(t1/16)=15/16 -> t1=1


If anybody has questions can write to me: laura81@blu.it (I teach GMAT in MILANO)
Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18663
Followers: 3228

Kudos [?]: 22128 [1] , given: 2595

Re: In the sequence of non-zero numbers t1, t2,t3,......tn,..... [#permalink] New post 23 Aug 2013, 02:25
1
This post received
KUDOS
Expert's post
riks200 wrote:
In the sequence of non-zero numbers t1, t2,t3,......tn,.....,tn+1 =tn/2 for all positive integers of n. What is the value of t5?

(1) t3 = 1/4
(2) t1 - t5 = 15/16


Given: t_{n+1}=\frac{t_n}{2}. So t_2=\frac{t_1}{2}, t_3=\frac{t_2}{2}=\frac{t_1}{4}, t_4=\frac{t_3}{2}=\frac{t_1}{8}, ...

Basically we have geometric progression with common ratio \frac{1}{2}: t_1, \frac{t_1}{2}, \frac{t_1}{4}, \frac{t_1}{8}, ... --> t_n=\frac{t_1}{2^{n-1}}.

Question: t_5=\frac{t_1}{2^4}=?

(1) t_3=\frac{1}{4} --> we can get t_1 --> we can get t_5. Sufficient.
(2) t_1-t_5=2^4*t_5-t_5=\frac{15}{16} --> we can get t_5. Sufficient.

Answer: D.

Generally for arithmetic (or geometric) progression if you know:

- any particular two terms,
- any particular term and common difference (common ratio),
- any particular term and the formula for n_th term,
- the sum of the sequence and either any term or common difference (common ratio),

then you will be able to calculate any missing value of given sequence.

Hope it helps.
OPEN DISCUSSION OF THIS QUESTION IS HERE: in-the-sequence-1-2-4-8-16-32-each-term-after-the-104175.html
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Re: In the sequence of non-zero numbers t1, t2,t3,......tn,.....   [#permalink] 23 Aug 2013, 02:25
    Similar topics Author Replies Last post
Similar
Topics:
In the sequence of nonzero numbers t1, t2, t3, , tn, , tn+1 goalsnr 5 10 Jul 2008, 22:49
7 Experts publish their posts in the topic In the sequence of nonzero numbers t1, t2, t3, , tn, , tn+1 quantum 7 18 Jun 2008, 09:23
If the terms of a sequence are t1, t2, t3,...tn what is the yezz 1 15 Oct 2006, 08:55
In the arithmetic sequence, t1, t2, t3, ........, tn, alimad 3 25 Sep 2006, 21:28
1 If the terms of a sequence are t1,t2,t3...tn what is the the dinesh8 4 07 May 2006, 17:08
Display posts from previous: Sort by

In the sequence of non-zero numbers t1, t2,t3,......tn,.....

  Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

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®.