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

 It is currently 27 Aug 2016, 01:14

### 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 June
Open Detailed Calendar

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

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

### Hide Tags

Intern
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]

### Show Tags

12 Jul 2008, 22:34
00:00

Difficulty:

45% (medium)

Question Stats:

68% (02:04) correct 32% (01:20) wrong based on 68 sessions

### HideShow timer Statistics

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
SVP
Joined: 29 Aug 2007
Posts: 2492
Followers: 66

Kudos [?]: 693 [0], given: 19

Re: DS Sequence [#permalink]

### Show Tags

12 Jul 2008, 23:02
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?
_________________

Gmat: http://gmatclub.com/forum/everything-you-need-to-prepare-for-the-gmat-revised-77983.html

GT

Director
Joined: 27 May 2008
Posts: 549
Followers: 8

Kudos [?]: 282 [0], given: 0

Re: DS Sequence [#permalink]

### Show Tags

12 Jul 2008, 23:51
there is a typo in the question, refer 7-t66979
Intern
Joined: 24 Jul 2013
Posts: 1
Followers: 0

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

Re: In the sequence of non-zero numbers t1, [#permalink]

### Show Tags

23 Aug 2013, 03:14
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)
Math Expert
Joined: 02 Sep 2009
Posts: 34449
Followers: 6274

Kudos [?]: 79605 [1] , given: 10022

In the sequence of non-zero numbers t1, t2,t3,......tn,..... [#permalink]

### Show Tags

23 Aug 2013, 03:25
1
KUDOS
Expert's post
1
This post was
BOOKMARKED
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.

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

- any particular two terms,
- any particular term and common difference (common ratio),
- 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
_________________
In the sequence of non-zero numbers t1, t2,t3,......tn,.....   [#permalink] 23 Aug 2013, 03:25
Similar topics Replies Last post
Similar
Topics:
If h1 and h2 are the number of households and t1 and t2 are the number 2 01 Nov 2015, 09:16
22 The numbers above form a sequence, t1, t2, and t3 , which is 9 13 Dec 2010, 07:59
16 Sequence S consists of 24 nonzero integers. If each term in 22 07 Aug 2010, 12:34
9 If the terms of a sequence are t1, t2, t3, . . . , tn, what 9 10 Jan 2009, 23:52
16 In the sequence of nonzero numbers t1, t2, t3, , tn, , tn+1 12 18 Jun 2008, 10:23
Display posts from previous: Sort by

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

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 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®.