Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 563 reviewsTarget Test Prep

two elements

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 226
Joined: Thu Nov 25, 2010 12:19 amFollowed by: 2 members
Thanked: 3 times
by nafiul9090 » Thu Jul 05, 2012 10:10 pm
how many two element subsets of (1,2,3,4) are there that do not contain the pair of elements 2 and 4

one
two
three
four
five
Top
Join the discussion
Source: — Problem Solving |
Master | Next Rank: 500 Posts
Posts: 363
Joined: Sun Oct 17, 2010 3:24 pmFollowed by: 3 members
Thanked: 115 times

by theCEO » Fri Jul 06, 2012 12:46 am
number of 2 element subsets = (4*3)/2 = 6

number of (2 and 4 elements) = 1 [only 1 arrangement]

therefore no of pairs that do not contain the pair of 2 and 4 = 6-1=5
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 141
Joined: Tue Oct 04, 2011 5:17 am
Thanked: 25 times

by coolhabhi » Fri Jul 06, 2012 4:54 am
IMO two.

take a list of all the two element subsets of (1,2,3,4). We have
(1,2) (1,3) (1,4)
(2,1) (2,3) (2,4)
(3,1) (3,2) (3,4)
(4,1) (4,2) (4,3)

An other way to look at it is :
If two elements are removed then the set will be (1,3).
So we can get on 2! subsets. that is 2.

BTW what is the OA?
Top
Join the discussion

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16206
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Fri Jul 06, 2012 5:48 am
nafiul9090 wrote:how many two element subsets of (1,2,3,4) are there that do not contain the pair of elements 2 and 4

one
two
three
four
five
Given the small numbers in the answer choices, another viable approach is to simply list the allowable outcomes:
(1,2), (1,3), (1,4), (2,3), (3,4)

So, the answer is E - five

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 363
Joined: Sun Oct 17, 2010 3:24 pmFollowed by: 3 members
Thanked: 115 times

by theCEO » Fri Jul 06, 2012 3:07 pm
coolhabhi wrote:IMO two.

take a list of all the two element subsets of (1,2,3,4). We have
(1,2) (1,3) (1,4)
(2,1) (2,3) (2,4)
(3,1) (3,2) (3,4)
(4,1) (4,2) (4,3)

An other way to look at it is :
If two elements are removed then the set will be (1,3).
So we can get on 2! subsets. that is 2.

BTW what is the OA?
I think you are answering the question - "How many 2-sets that do not contain either 2 or 4?"
Top
Join the discussion