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

Selecting door

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 105
Joined: Tue May 13, 2014 10:41 amFollowed by: 1 member
Thanked: 2 times
by nahid078 » Wed Jul 01, 2015 11:45 am
In how many ways 2 doors be selected from 3 doors for entering and leaving the room?

1) 1
2) 3
3) 6
4) 9
50 12
Top
Join the discussion
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 154
Joined: Wed May 21, 2014 4:29 amFollowed by: 1 member
Thanked: 8 times

by talaangoshtari » Wed Jul 01, 2015 12:17 pm
3C1 = 3, so in 3 ways we can choose a door. Since the doors for entering and leaving the room are the same, the answer is 3
Last edited by talaangoshtari on Wed Jul 01, 2015 10:38 pm, edited 1 time in total.
Top
Join the discussion

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2623
Joined: Mon Jun 02, 2008 3:17 amFollowed by: 355 members
Location: Montreal
Thanked: 1090 times
GMAT Score:780

by Ian Stewart » Wed Jul 01, 2015 1:38 pm
It's not clear what the question means, because the wording is not precise. I'd assume that we can use the same door to enter and leave, and that it matters which door we use to enter, and which we use to leave. Under those assumptions, we have 3 choices for the enter door, and 3 for the exit door, so 3*3 = 9 choices in total.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com
Top
Join the discussion
Legendary Member
Posts: 518
Joined: Tue May 12, 2015 8:25 pm
Thanked: 10 times

by nikhilgmat31 » Fri Jul 03, 2015 12:23 am
I think question is asking to choose 2 doors out of 3 in a room.
1 to enter & 1 to leave

A,B,C are three doors & we need to choose 2 doors where order matters. - so answer is 3!/1! = 6

A,B
B,A
A,C
C,A
A,B
B,A
Top
Join the discussion
Legendary Member
Posts: 518
Joined: Tue May 12, 2015 8:25 pm
Thanked: 10 times

by nikhilgmat31 » Thu Jul 09, 2015 1:28 am
if we can use wither same of different doors to enter/exit.

number of ways is 3*3 = 9
Top
Join the discussion
Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Sun Sep 04, 2016 10:01 pm

by timur12 » Sun Sep 04, 2016 10:05 pm
Assuming different doors to be used:
The problem can be divided in 2 steps.
1) First select the door(assuming doors can be differentiated based on something).

3 ways

2) Then choose which door to use for entry and exit.

2 ways

Total ways 3*2 = 6 ways
Top
Join the discussion
GMAT Instructor
Posts: 2629
Joined: Wed Sep 12, 2012 3:32 pmFollowed by: 119 members
Location: East Bay all the way
Thanked: 625 times
GMAT Score:780

by Matt@VeritasPrep » Thu Sep 15, 2016 8:04 pm
It all depends on whether you can use the same door to enter and leave. The GMAT would specify, I think, so this isn't the best question.
Top
Join the discussion