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

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 248
Joined: Mon Aug 11, 2008 9:51 am
Thanked: 13 times
by earth@work » Wed Oct 08, 2008 5:01 pm
In a lottery, a person choses six different natural numbers at random from 1 to 20, and if these six numbers match with the six numbers already fixed by the lottery committee, he wins the prize. What is the probability of Winning the prize in the game.
Top
Join the discussion
Source: — Problem Solving |
User avatar
Master | Next Rank: 500 Posts
Posts: 248
Joined: Mon Aug 11, 2008 9:51 am
Thanked: 13 times

by earth@work » Thu Oct 09, 2008 9:53 am
pls help.... answer is 1/38760
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 145
Joined: Mon Sep 29, 2008 1:14 am
Thanked: 13 times

by mental » Thu Oct 09, 2008 10:14 am
just think it slighly different manner

how many ways can 6 numbers be chosen out of 20 numbers

they are not asking arrangements

20c6 = 20!/14!*6! = solve it you get 38760

one combination is selected out of it by selectors

probability = 1/38760
Top
Join the discussion
User avatar
Master | Next Rank: 500 Posts
Posts: 248
Joined: Mon Aug 11, 2008 9:51 am
Thanked: 13 times

by earth@work » Thu Oct 09, 2008 10:30 am
thanks a lot!
Top
Join the discussion
Legendary Member
Posts: 891
Joined: Sat Aug 16, 2008 4:21 amFollowed by: 1 member
Thanked: 27 times
GMAT Score:660(

by 4meonly » Sat Oct 11, 2008 12:32 am
I doubt whether this Q is correct

4me, the probability will be

1/20 * 1/19 * 1/18 * 1/17 * 1/16 * 1/15 we'll get less then 1/38760

Because 123456 is not the same as 654321

answer 1/38760 assumens that order is not important but it should be important!!!
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 145
Joined: Mon Sep 29, 2008 1:14 am
Thanked: 13 times

Re: probability

by mental » Sat Oct 11, 2008 7:41 am
earth@work wrote:In a lottery, a person choses six different natural numbers at random from 1 to 20, and if these six numbers match with the six numbers already fixed by the lottery committee, he wins the prize. What is the probability of Winning the prize in the game.
the quaestion is not talking about arrangements

also just think that it has double digit numbers
20, 19, 8, 7 are actually only four numbers, but if we write in one go....201987...can also mean...2,0,1,9,8,7...6 different numbers!!!!

neways thats im-material
Top
Join the discussion
Master | Next Rank: 500 Posts
Posts: 154
Joined: Tue Aug 26, 2008 12:59 pm
Location: Canada
Thanked: 4 times

by canuckclint » Sat Oct 11, 2008 9:25 am
4meonly wrote:I doubt whether this Q is correct

4me, the probability will be

1/20 * 1/19 * 1/18 * 1/17 * 1/16 * 1/15 we'll get less then 1/38760

Because 123456 is not the same as 654321

answer 1/38760 assumens that order is not important but it should be important!!!
This does take into account order. Since the first number is 1/20 chance and so on.
Its just the probability happens to be the same if they are switched.
For example. what is the probability of coin toss:
TTH or HTT are the same 1/8

Makes sense?
Top
Join the discussion
Junior | Next Rank: 30 Posts
Posts: 13
Joined: Wed May 21, 2008 8:31 pm

by hgupta0 » Tue Dec 30, 2008 4:57 pm
I think the problem with the question is that it does not specify anything about order. Re-reading the question again it seems the condition for winning is that 6 numbers match with the numbers defined by the committee. Hence order does not matter
- H
4meonly wrote:I doubt whether this Q is correct

4me, the probability will be

1/20 * 1/19 * 1/18 * 1/17 * 1/16 * 1/15 we'll get less then 1/38760

Because 123456 is not the same as 654321

answer 1/38760 assumens that order is not important but it should be important!!!
Top
Join the discussion
Legendary Member
Posts: 621
Joined: Wed Apr 09, 2008 7:13 pmFollowed by: 4 members
Thanked: 33 times

by vittalgmat » Wed Dec 31, 2008 4:41 am
well the Q is ambigous.

If all the 6 numbers are considered together as 6digit number then it is permutations

If the 6 numbers are considered as 6 individual numbers then,
it is combination.

HT helps
Top
Join the discussion