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

It is currently 29 Jul 2015, 02:20
GMAT Club Tests

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

Find an integer F

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
SVP
SVP
User avatar
Joined: 03 Feb 2003
Posts: 1607
Followers: 6

Kudos [?]: 93 [0], given: 0

Find an integer F [#permalink] New post 21 May 2003, 23:57
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  25% (medium)

Question Stats:

57% (01:41) correct 43% (00:39) wrong based on 201 sessions
Find an integer F.

(1) F = 1/F
(2) |F| = 1/F
[Reveal] Spoiler: OA
Manager
Manager
avatar
Joined: 07 May 2013
Posts: 109
Followers: 0

Kudos [?]: 13 [0], given: 1

Re: Find an integer F [#permalink] New post 06 Jun 2014, 00:41
S1
After looking at the equations that this equations con only hold true for 1, -1.
S1 holds true for both.

S2
This equation is true only when F=1.

So, the integer that we are looking for is 1.

Hence, B.
Moderator
Moderator
User avatar
Joined: 25 Apr 2012
Posts: 734
Location: India
GPA: 3.21
WE: Business Development (Other)
Followers: 29

Kudos [?]: 443 [0], given: 723

Premium Member Reviews Badge
Re: Find an integer F [#permalink] New post 06 Jun 2014, 01:01
stolyar wrote:
Find an integer F.

(1) F = 1/F
(2) |F| = 1/F


St:1 F=1/F or F- 1/F =0

F^2- 1/F=0, Now F cannot be equal to 0
So F^2-1= 0 or F =+1 or -1
Not sufficient

St 2 |F|=1/F

Now LHS is mod value and hence always non-negative. Therefore \(|F|\geq{0}\) or \(1/F\geq{0}\)
Note that F cannot be equal to zero as otherwise the expression becomes undefined.

Therefore |F| >0 or 1/F >0 -----Thus F>0

Since F>0 So we have F= 1/F or F^2=1 and F =1 as F >0
Ans is B

C is Trap answer here
_________________


“If you can't fly then run, if you can't run then walk, if you can't walk then crawl, but whatever you do you have to keep moving forward.”

Manager
Manager
avatar
Joined: 07 Apr 2015
Posts: 91
Followers: 0

Kudos [?]: 14 [0], given: 110

Find an integer F [#permalink] New post 09 Jul 2015, 01:30
For statement 2) I would try both cases:

I:
\(F = \frac{1}{F}\)
\(F^2 = 1\)
\(F = 1\)


II:
\(- F = \frac{1}{F}\)
\(- F^2 = 1\)
\(F^2 = -1\)


Root of a negative number is not possible, i.e. this one does not work. Leaves the first option -> sufficient to answer the question!
Find an integer F   [#permalink] 09 Jul 2015, 01:30
    Similar topics Author Replies Last post
Similar
Topics:
2 Experts publish their posts in the topic If n is an integer and f(n) = f(n 1) n, what is the value of lyss3b 10 15 Jun 2011, 14:30
3 Experts publish their posts in the topic For all integers n, the function f is defined by f (n) = RenukaD 3 22 Jul 2010, 09:45
21 Experts publish their posts in the topic If d is a positive integer and f is the product of the first zoom 69 10 Sep 2005, 11:58
1 Experts publish their posts in the topic For all integers n, the function f is defined by f(n)=a^n gmatraj 5 11 Jul 2009, 09:26
1 Experts publish their posts in the topic For all integers n, the function f is defined by f (n) = a^n sperumba 7 17 Jan 2006, 17:20
Display posts from previous: Sort by

Find an integer F

  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®.