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

Probability Query

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
Newbie | Next Rank: 10 Posts
Posts: 1
Joined: Fri Apr 22, 2011 7:27 am
by sinha » Thu Jun 30, 2011 10:25 am
Can someone help me understand this question :

n question are either true or false. What is the minimum value of n for which (p) of all true <1/1000?

thanx :)
Top
Join the discussion
Source: — Problem Solving |
Legendary Member
Posts: 1448
Joined: Tue May 17, 2011 9:55 amFollowed by: 53 members
Location: India
Thanked: 375 times

by Frankenstein » Thu Jun 30, 2011 10:40 am
Hi,
Probability that each each question is correct is 1/2.
So, probability of gettign all 'n' questions correct is (1/2)^n
So, (1/2)^n < 1/1000 => 2^n > 1000
2^10 = 1024
So, n >= 10
Minimum value of n is 10.
Last edited by Frankenstein on Thu Jun 30, 2011 8:33 pm, edited 1 time in total.
Cheers!

Things are not what they appear to be... nor are they otherwise
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 33
Joined: Fri Aug 22, 2008 9:32 pm
Thanked: 1 times

by treker » Thu Jun 30, 2011 7:11 pm
Frankenstein wrote:Hi,
Probability that each each question is correct is 1/2.
So, probability of gettign all 'n' questions correct is (1/2)^n
So, (1/2)^n < 1000 => 2^n > 1000
2^10 = 1024
So, n >= 10
Minimum value of n is 10.
Can you please explain this stmt - "So, (1/2)^n < 1000 => 2^n > 1000"
Thanks!
- Treker
Top
Join the discussion
Legendary Member
Posts: 1448
Joined: Tue May 17, 2011 9:55 amFollowed by: 53 members
Location: India
Thanked: 375 times

by Frankenstein » Thu Jun 30, 2011 8:29 pm
treker wrote:
Frankenstein wrote:Hi,
Probability that each each question is correct is 1/2.
So, probability of gettign all 'n' questions correct is (1/2)^n
So, (1/2)^n < 1000 => 2^n > 1000
2^10 = 1024
So, n >= 10
Minimum value of n is 10.
Can you please explain this stmt - "So, (1/2)^n < 1000 => 2^n > 1000"
Hi,
That was a typo. I have edited now. If you are interested in the underlying principle,
If a and b are positive and a > b, then 1/a < 1/b.
Example: 3>2 .. 1/3 < 1/2.
Cheers!

Things are not what they appear to be... nor are they otherwise
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 461
Joined: Tue May 10, 2011 9:09 amFollowed by: 3 members
Location: pune
Thanked: 36 times

by amit2k9 » Thu Jun 30, 2011 9:18 pm
probability of having a right or wrong in question = 1/2

thus 1/2^n < 1/1000 is what being asked here.

hence 2^n = 1024 is sufficient meaning n = 10.
For Understanding Sustainability,Green Businesses and Social Entrepreneurship visit -https://aamthoughts.blocked/
(Featured Best Green Site Worldwide-https://bloggers.com/green/popular/page2)
Top
Join the discussion