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

It is currently 30 Sep 2014, 09:58

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

A set of numbers has the property that for any number t in

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Director
Director
User avatar
Joined: 08 Jul 2004
Posts: 606
Followers: 2

Kudos [?]: 36 [0], given: 0

A set of numbers has the property that for any number t in [#permalink] New post 12 Apr 2005, 08:30
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  35% (medium)

Question Stats:

54% (01:26) correct 46% (00:34) wrong based on 95 sessions
A set of numbers has the property that for any number t in the set, t + 2 is in the set. If -1 is in the set, which of the following must also be in the set?

I. -3
II. 1
III. 5

(A) I only
(B) II only
(C) I and II only
(D) II and III only
(E) I, II, and III

OPEN DISCUSSION OF THIS QUESTION IS HERE: a-set-of-numbers-has-the-property-that-for-any-number-t-in-t-98829.html
[Reveal] Spoiler: OA

_________________

Regards, S


Last edited by Bunuel on 04 Aug 2012, 03:00, edited 2 times in total.
Edited the question and added the OA.
Kaplan Promo CodeKnewton GMAT Discount CodesGMAT Pill GMAT Discount Codes
1 KUDOS received
Senior Manager
Senior Manager
avatar
Joined: 19 Feb 2005
Posts: 492
Location: Milan Italy
Followers: 1

Kudos [?]: 9 [1] , given: 0

 [#permalink] New post 12 Apr 2005, 09:19
1
This post received
KUDOS
D for me.
We know for sure that t (-1) is in the set
so t+2=+1 is in the set
so 1+2=3 is in the set
so 3+2=5 is in the set

-1 could be the first element of the set, so -3 can't be said to belong to the set
Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 23063
Followers: 3537

Kudos [?]: 27223 [1] , given: 2725

Re: A set of numbers has the property that for any number t in [#permalink] New post 04 Aug 2012, 03:00
1
This post received
KUDOS
Expert's post
imhimanshu wrote:
Hi,
Can someone please clarify my doubts..

Question is
A set of numbers has the property that for any number t in the set, t + 2 is in the set. If -1
is in the set, which of the following must also be in the set?

Doubt 1 -
Lets say t= -1 ; then t+2 is is set = i.e. 1 is in set.

Since question stem is Must be True, how do we make sure that this pattern will continue.
i.e if 1 is in set, then 3 will be in set and so on..

Also

Doubt 2 -
Cant we assume that
t+2 = -1
then t= -3(should also be in set)

Please clarify.

Thanks


A set of numbers has the property that for any number t in the set, t + 2 is in the set. If -1 is in the set, which of the following must also be in the set?

I. -3
II. 1
III. 5

(A) I only
(B) II only
(C) I and II only
(D) II and III only
(E) I, II, and III

The question is which of the following must be in the set, not could be in the set.

If -1 is in the set so must be -1+2=1, as 1 is in the set so must be 1+2=3, as 3 is in the set so must be 3+2=5 and so on. So basically knowing that -1 is in the set we can say that ALL odd numbers more than -1 are also in the set.

Answer: D.

Now, about your questions:
1. The question says "a set of numbers has the property that for ANY number t in the set, t + 2 is in the set", so if 1 is in the set then 1+2=3 MUST be in the set.

2. We don't know which is the source integer in the set, if it's -1 than odd number less than it won't be in the set but if source integer is let's say -11 than -3 will be in the set. So -3 may or may not be in the set.

Similar questions to practice:
for-a-certain-set-of-numbers-if-x-is-in-the-set-then-x-136580.html
if-p-is-a-set-of-integers-and-3-is-in-p-is-every-positive-96630.html
k-is-a-set-of-integers-such-that-if-the-integer-r-is-in-k-103005.html
k-is-a-set-of-numbers-such-that-i-if-x-is-in-k-then-x-96907.html

OPEN DISCUSSION OF THIS QUESTION IS HERE: a-set-of-numbers-has-the-property-that-for-any-number-t-in-t-98829.html
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Director
Director
User avatar
Joined: 08 Jul 2004
Posts: 606
Followers: 2

Kudos [?]: 36 [0], given: 0

 [#permalink] New post 12 Apr 2005, 10:18
thearch wrote:
D for me.
We know for sure that t (-1) is in the set
so t+2=+1 is in the set
so 1+2=3 is in the set
so 3+2=5 is in the set

-1 could be the first element of the set, so -3 can't be said to belong to the set

I am not sure ; if -1 is in the set then either it is t ot t+2. if it is t, then the other number is t+2 ie 1. If -1 is t+2 then, t is -3. So according to me answer should be C.
_________________

Regards, S

VP
VP
avatar
Joined: 18 Nov 2004
Posts: 1447
Followers: 2

Kudos [?]: 16 [0], given: 0

 [#permalink] New post 12 Apr 2005, 10:47
"B"....ques says for a number t , t+2 shd be there we know -1 is there so
-1+2 = 1 MUST be there. I don't think we can extrapolate this and make this an infinite series. Surya do u have the OA ?
Senior Manager
Senior Manager
avatar
Joined: 15 Mar 2005
Posts: 425
Location: Phoenix
Followers: 1

Kudos [?]: 9 [0], given: 0

 [#permalink] New post 12 Apr 2005, 16:37
banerjeea_98 wrote:
"B"....ques says for a number t , t+2 shd be there we know -1 is there so
-1+2 = 1 MUST be there. I don't think we can extrapolate this and make this an infinite series. Surya do u have the OA ?


Hey Baner, but we already have this as an infinite series in one direction (positive). But I agree with you - this could be an infinite series in one direction, starting with -1. So we cannot assume the presence of numbers lower than -1.
_________________

Who says elephants can't dance?

Senior Manager
Senior Manager
avatar
Joined: 25 Oct 2004
Posts: 250
Followers: 1

Kudos [?]: 5 [0], given: 0

 [#permalink] New post 12 Apr 2005, 16:54
I think the answer should be D. I think its safe o assume that the series is an infinite series starting with -1. Any thoughts???

Whats the OA
Director
Director
avatar
Joined: 18 Feb 2005
Posts: 674
Followers: 1

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

 [#permalink] New post 12 Apr 2005, 19:04
banerjeea_98 wrote:
"B"....ques says for a number t , t+2 shd be there we know -1 is there so
-1+2 = 1 MUST be there. I don't think we can extrapolate this and make this an infinite series. Surya do u have the OA ?


if t+2 exists in the set then it would be t for another number......So it should be valid for all the numbers given.

A number's existence is enough to qualify itself to become t
VP
VP
avatar
Joined: 18 Nov 2004
Posts: 1447
Followers: 2

Kudos [?]: 16 [0], given: 0

 [#permalink] New post 12 Apr 2005, 20:03
I agree this is another of those controversial ques, u can argue it both ways....let's wait for the OA...I bet OA is not "E" :wink: Surya can u post OA plz and OE if available.
VP
VP
User avatar
Joined: 25 Nov 2004
Posts: 1498
Followers: 6

Kudos [?]: 31 [0], given: 0

Re: PS Set of numbers [#permalink] New post 12 Apr 2005, 21:40
I was thinking B first. but, what does "A set of numbers has the property that for any number t in the set, t + 2 is in the set"?

i think any number indicates to an infinite series. if so, it should be E.
t could be any number in the series. if t is in the series, t+2 is also in the series. if t=t+2, then t+2=t+4. then if t+2=t, then t=t-2.

Correct, if any........
Senior Manager
Senior Manager
avatar
Joined: 19 Feb 2005
Posts: 492
Location: Milan Italy
Followers: 1

Kudos [?]: 9 [0], given: 0

 [#permalink] New post 13 Apr 2005, 02:08
saurya_s wrote:
I am not sure ; if -1 is in the set then either it is t ot t+2. if it is t, then the other number is t+2 ie 1. If -1 is t+2 then, t is -3. So according to me answer should be C.


you're right, but the stem doesn't ask for numbers that COULD be in the set (because I agree with you that -3 COULD be in the set, but we're not sure of that, so we can't say that it MUST be there)

desperately waiting for the OA
Intern
Intern
avatar
Joined: 11 Mar 2005
Posts: 23
Followers: 0

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

 [#permalink] New post 13 Apr 2005, 03:32
banerjeea_98 wrote:
"B"....ques says for a number t , t+2 shd be there we know -1 is there so
-1+2 = 1 MUST be there. I don't think we can extrapolate this and make this an infinite series. Surya do u have the OA ?


Question says if t is there, then t+2 must be there. That's an infinite series, if ever there was one. However, we can only be sure of this series in one direction

Go with D.
Director
Director
avatar
Joined: 27 Dec 2004
Posts: 910
Followers: 1

Kudos [?]: 12 [0], given: 0

 [#permalink] New post 13 Apr 2005, 05:52
I pick C.

Let t = -1,
Then we know t + 2 = -1 + 2 = 1.

Then let t + 2 = -1
Then t = -1 -2 = -3

All other info that can be applied are assumptions so for sure I think 1 and -3 are certainly in the set thus C.
Director
Director
avatar
Joined: 27 Dec 2004
Posts: 910
Followers: 1

Kudos [?]: 12 [0], given: 0

 [#permalink] New post 13 Apr 2005, 05:54
Same reasoning here.
I anticipate the OA though
Director
Director
User avatar
Joined: 08 Jul 2004
Posts: 606
Followers: 2

Kudos [?]: 36 [0], given: 0

 [#permalink] New post 13 Apr 2005, 13:14
The OA I have got is D. I am not convinced though. Why it has to go in postive direction only. For me it should be C. can any one justify D as answer convincingly.
S
_________________

Regards, S

SVP
SVP
User avatar
Joined: 03 Jan 2005
Posts: 2255
Followers: 12

Kudos [?]: 200 [0], given: 0

Re: PS Set of numbers [#permalink] New post 14 Apr 2005, 13:45
saurya_s wrote:
A set of numbers has the property that for any number t in the set, t + 2 is in the set. If –1
is in the set, which of the following must also be in the set?
I. -3
II. 1
III. 5


If -1 is in the set, then -1+2=1 is in the set, then 1+2=3 is in the set, then 3+2=5 is in the set. We don't know about -3, however, since we don't have t-2 in the set if t in the set.

The answer is D.
_________________

Keep on asking, and it will be given you;
keep on seeking, and you will find;
keep on knocking, and it will be opened to you.

Senior Manager
Senior Manager
avatar
Joined: 07 Sep 2010
Posts: 340
Followers: 3

Kudos [?]: 138 [0], given: 136

Re: A set of numbers has the property that for any number t in [#permalink] New post 04 Aug 2012, 02:28
Hi,
Can someone please clarify my doubts..

Question is
A set of numbers has the property that for any number t in the set, t + 2 is in the set. If -1
is in the set, which of the following must also be in the set?

Doubt 1 -
Lets say t= -1 ; then t+2 is is set = i.e. 1 is in set.

Since question stem is Must be True, how do we make sure that this pattern will continue.
i.e if 1 is in set, then 3 will be in set and so on..

Also

Doubt 2 -
Cant we assume that
t+2 = -1
then t= -3(should also be in set)

Please clarify.

Thanks
_________________

+1 Kudos me, Help me unlocking GMAT Club Tests

Re: A set of numbers has the property that for any number t in   [#permalink] 04 Aug 2012, 02:28
    Similar topics Author Replies Last post
Similar
Topics:
Experts publish their posts in the topic A set of numbers has the property that for any number t in saviop 8 19 Nov 2007, 18:06
A set of numbers has the property that for any number t in IrinaOK 3 22 Oct 2007, 19:00
A set of numbers has the property that for any number t in acfuture 10 15 Jul 2006, 19:06
A set of numbers has the property that for any number t in JAI HIND 4 29 Dec 2005, 23:38
A set of numbers has the property that for any number t in trickygmat 27 17 Oct 2005, 06:49
Display posts from previous: Sort by

A set of numbers has the property that for any number t in

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

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®.