GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 19 Oct 2018, 08:38

Fuqua EA Calls in Progress:

Join us in the chat | track the decision tracker | See forum posts/summary


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.

Close

Request Expert Reply

Confirm Cancel

If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of

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

Hide Tags

Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 50002
If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of  [#permalink]

Show Tags

New post 13 Feb 2017, 03:21
00:00
A
B
C
D
E

Difficulty:

  15% (low)

Question Stats:

84% (01:41) correct 16% (01:36) wrong based on 80 sessions

HideShow timer Statistics

Intern
Intern
avatar
B
Joined: 09 Sep 2016
Posts: 35
Location: Georgia
Concentration: Finance, International Business
GPA: 3.75
WE: Analyst (Investment Banking)
Re: If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of  [#permalink]

Show Tags

New post 13 Feb 2017, 04:50
as i get, next term = previous term + 1
f(7+1)=f(7)+1 => f(8) = 4... f(6+1)=F(6)+1 so 3=f(6)+1=> f(6) = 2
so f(5)= 1 ; f(4)=0 and f(3) = -1

a thing answer is A
Director
Director
avatar
S
Joined: 21 Mar 2016
Posts: 526
Reviews Badge
Re: If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of  [#permalink]

Show Tags

New post 13 Feb 2017, 05:53
f(6) = 2... similarly f(3) is -1
ans A
Target Test Prep Representative
User avatar
P
Status: Founder & CEO
Affiliations: Target Test Prep
Joined: 14 Oct 2015
Posts: 3888
Location: United States (CA)
Re: If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of  [#permalink]

Show Tags

New post 14 Feb 2017, 16:52
2
Bunuel wrote:
If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of f(3)?

A. -1
B. 3
C. 7
D. 11
E. 13



We are given that f(x+1) = f(x) + 1 for all values of x and that f(7) = 3. We will be working “backward” to determine the value of f(3).

Let x = 6; then f(6+1) = f(6) + 1, i.e., f(7) = f(6) + 1.

Since f(7) = 3, we have 3 = f(6) + 1, i.e., f(6) = 2.

Let x = 5; then f(5+1) = f(5) + 1, i.e., f(6) = f(5) + 1.

Since f(6) = 2, we have 2 = f(5) + 1, i.e., f(5) = 1.

Let x = 4; then f(4+1) = f(4) + 1, i.e., f(5) = f(4) + 1.

Since f(5) = 1, we have 1 = f(4) + 1, i.e., f(4) = 0.

Let x = 3; then f(3+1) = f(3) + 1, i.e., f(4) = f(3) + 1.

Since f(4) = 0, we have 0 = f(3) + 1, i.e., f(3) = -1.

Answer: A
_________________

Scott Woodbury-Stewart
Founder and CEO

GMAT Quant Self-Study Course
500+ lessons 3000+ practice problems 800+ HD solutions

Director
Director
avatar
S
Joined: 12 Nov 2016
Posts: 749
Location: United States
Schools: Yale '18
GMAT 1: 650 Q43 V37
GRE 1: Q157 V158
GPA: 2.66
Re: If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of  [#permalink]

Show Tags

New post 20 Feb 2017, 18:06
Um this one is kind of tripping me out but I'd say- If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of f(3)?- then the answer that follows is "A."
Math Expert
User avatar
V
Joined: 02 Aug 2009
Posts: 6960
Re: If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of  [#permalink]

Show Tags

New post 20 Feb 2017, 18:54
1
Bunuel wrote:
If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of f(3)?

A. -1
B. 3
C. 7
D. 11
E. 13



Hi...
A simpler way is to look at the choices..

Each term is ONE more than the previous term... F(x+1)=F(x)+1...

So if F(7) =3, F(3) has to be lesser than 3..
Only A is less than 3..

If you want to find exact answer, again no need to get into finding each term..
Difference in 7th and 3rd term is 4, so F(3) = F(7)-4=3-4=-1

A
_________________

1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372
2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html
3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html


GMAT online Tutor

GMAT Club Bot
Re: If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of &nbs [#permalink] 20 Feb 2017, 18:54
Display posts from previous: Sort by

If f(x+1)=f(x)+1 for all values of x, and f(7)=3, what is the value of

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


cron
Copyright

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

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

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®.