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

 It is currently 28 Apr 2015, 06:41

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

statement 1+2 gives us x4/2 = x4/(x4+1) here we are equating

Author Message
TAGS:
Intern
Joined: 09 Sep 2007
Posts: 10
Followers: 0

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

statement 1+2 gives us x4/2 = x4/(x4+1) here we are equating [#permalink]  18 Jun 2008, 07:52
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 0 sessions
Hi Guys,
This is regarding the post I was going through..
My question is

statement 1+2 gives us
x4/2 = x4/(x4+1)
here we are equating x4+1=2 => x4=1

why dont we cross multiply here which gives us x4=0 or 1?

original post:
Question: Given x1, x2, x3, ...; What is x1?

...(1) Xi = Xi-1/2
e.g. X2 = X1/2, X3 = X2/2
No number to find x1. INSUFF

...(2) x5 = x4/(x4 + 1)
No number to find x1. INSUFF

...(1) + (2);

Now we know the format Xi = Xi-1/2
and X5 = X4/(X4+1)

Clearly, X4 + 1 = 2
X4 = 2-1 = 1

X4 = (X3)/2 = 1; X3 = 2
X3 = (X2)/2 = 2; X2 = 4
..Keep going and you will know X1. Thus, (1) + (2) SUFF.
Director
Joined: 12 Apr 2008
Posts: 500
Location: Eastern Europe
Schools: Oxford
Followers: 12

Kudos [?]: 176 [0], given: 4

Re: DS question [#permalink]  18 Jun 2008, 12:54
Hi, shmistry,

In general, the cross-multiplication would be the correct approach to the solution. However, in this particular case, it is explicitly stated that all xi are positive – read the problem carefully (see the link below). So, x4 can’t be zero.

http://www.gmatclub.com/forum/7-t41982
Re: DS question   [#permalink] 18 Jun 2008, 12:54
Similar topics Replies Last post
Similar
Topics:
OG 12- Q:2 can we use may instead of might? 0 06 Sep 2013, 05:33
2 OG12/126 - Here's the modified sentence : "The use of 2 13 Apr 2011, 18:54
How to use Denial here? 12.The upcoming presidential 13 09 Apr 2009, 10:23
My argument here is that Statement-1 is insufficient here. 8 03 Jun 2007, 19:37
Are we underestimating are chances here? 40 04 Nov 2006, 23:21
Display posts from previous: Sort by