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

 It is currently 07 Mar 2014, 22:03

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# If the sequence x1, x2, x3, , xn, is such that x1 = 3 and

 Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Senior Manager
Joined: 17 Aug 2005
Posts: 395
Location: Boston, MA
Followers: 1

Kudos [?]: 3 [0], given: 0

If the sequence x1, x2, x3, , xn, is such that x1 = 3 and [#permalink]  25 Mar 2006, 13:50
00:00

Difficulty:

5% (low)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
If the sequence x1, x2, x3, â€¦, xn, â€¦ is such that x1 = 3 and xn+1 = 2xn â€“ 1 for n = 1, then x20 â€“ x19 =
A. 219
B. 220
C. 221
D. 220 - 1
E. 221 - 1

I had trouble setting up the sequence formula, can anyone help?

OA to follow
Manager
Joined: 20 Nov 2004
Posts: 109
Followers: 0

Kudos [?]: 2 [0], given: 0

Re: PS-sequence [#permalink]  25 Mar 2006, 15:22
Well the answer seems to be 2^19 and A (although your A states 219).
Just write down the first elements and compute the differences.

x1=3
x2=5
x3=9
x4=17

So
x2=x1+2^1
x3=x2+2^2
x4=x3+2^3
... and
x20=x19+2^19, so

x20-x19=2^19.
Re: PS-sequence   [#permalink] 25 Mar 2006, 15:22
Similar topics Replies Last post
Similar
Topics:
If the sequence x1, x2, x3,..., xn,... is such that x1=3 and 7 18 Feb 2005, 08:54
If the sequence x1, x2, x3, , xn, is such that x1 = 3 and 6 28 Nov 2005, 07:10
If the sequence x1, x2,x3,...,xn is such that X1=3 and Xn+1 5 06 May 2008, 11:05
1 If the sequence x{_1} , x{_2} , x{_3} , ...., x{_n} , ....is 3 17 Jul 2008, 02:03
If the sequence X1, X2, X3, , Xn, is such thatX1 = 3 andXn+1 3 12 Nov 2008, 07:39
Display posts from previous: Sort by

# If the sequence x1, x2, x3, , xn, is such that x1 = 3 and

 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®.