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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 500,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

A contest will consist of n questions, each of which is to [#permalink]

Show Tags

27 Dec 2007, 08:28

5

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

5% (low)

Question Stats:

79% (01:50) correct
21% (00:57) wrong based on 169 sessions

HideShow timer Statistics

A contest will consist of n questions, each of which is to be answered either "true" or " false". anyone who answers all n questions correctly will be a winner. what is the least value of n for which the probability is less than 1/1000 that a person who randomly guesses the answer to each question will be a winner?

Re: A contest will consist of n questions, each of which is to [#permalink]

Show Tags

27 Dec 2007, 09:37

Each question has 2 ways to guess so the probability of guessing correctly is 1/2. The probability of guessing each question correctly for n questions is 1/2^n. What is the smallest number for n that gets the denominator over 1000?

1/2^n = probability

1/2^5 = 1/32
1/2^10 = 1/1024

and you don't need to go any further. Someone guessing on 10 questions has a 1/1024 chance of getting them all correct.

Re: A contest will consist of n questions, each of which is to [#permalink]

Show Tags

27 Sep 2009, 10:29

A contest will consist of n questions, each of which is to be answered either "true" or " false". anyone who answers all n questions correctly will be a winner. what is the least value of n for which the probability is less than 1/1000 that a person who randomly guesses the answer to each question will be a winner?

A.5 B.10 C.50 D.100 E.1000

Soln: ans is B

Probability that one question is answered right is 1/2.

Now for minimum number of questions needed to take probability less than 1/1000 is => (1/2)^n < 1/1000 n = 10 satisfies this.

Re: A contest will consist of n questions, each of which is to [#permalink]

Show Tags

09 Dec 2014, 20:58

Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

A contest will consist of n questions, each of which is to be answered either "True" or "False." Anyone who answers all n questions correctly will be a winner. What is the least value of n for which the probability is less than 1/1000 that a person who randomly guesses the answer to each question will be winner?

A. 5 B. 10 C. 50 D. 100 E. 1000

The probability to randomly guess the answer for 1 question is 1/2, for 2 questions 1/2*1/2=1/2^2, similarly for n questions the probability is 1/2^n.

We need to find the least value of \(n\) for which \(\frac{1}{2^n}<\frac{1}{1,000}\) --> \(2^n>1,000\) --> \(n_{min}=10\).

Campus visits play a crucial role in the MBA application process. It’s one thing to be passionate about one school but another to actually visit the campus, talk...

Its been long time coming. I have always been passionate about poetry. It’s my way of expressing my feelings and emotions. And i feel a person can convey...

Marty Cagan is founding partner of the Silicon Valley Product Group, a consulting firm that helps companies with their product strategy. Prior to that he held product roles at...

Written by Scottish historian Niall Ferguson , the book is subtitled “A Financial History of the World”. There is also a long documentary of the same name that the...