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 350,000 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 certain junior class has 1000 students and a certain [#permalink]
05 Jan 2008, 13:23

1

This post was BOOKMARKED

00:00

A

B

C

D

E

Difficulty:

(N/A)

Question Stats:

81% (01:59) correct
19% (01:02) wrong based on 24 sessions

A certain junior class has 1000 students and a certain senior class has 800 students. Among these students, there are 60 sibling pairs, each consisting of 1 junior and 1 senior.If 1 student is to be selected at random from each class, what is the probability that the 2 students selected will be a sibling pair? A: 3/40000 B: 1/3600 C:9/2000 D: 1/60 E:1/15 OA is A. Can someone please explain this problem in detail? Logic says since there are 60 sibling pairs: There are 30 seniors and 30 juniors So probability is p= 30/1000* 30/800. Why is this wrong?

60 pairs of siblings = 120 people; 60 juniors and 60 seniors; Probability of selecting a junior out of the class of 1000 people is 60/1000. Probability of selecting his/her sibling out of the class of seniors is 1/800 (since only one person can be his/her sibling);

A certain junior class has 1000 students and a certain senior class has 800 students. Among these students, there are 60 sibling pairs, each consisting of 1 junior and 1 senior.If 1 student is to be selected at random from each class, what is the probability that the 2 students selected will be a sibling pair? A: 3/40000 B: 1/3600 C:9/2000 D: 1/60 E:1/15

Soln: Total no. of ways of choosing two people, one from each class is 800 * 1000. Of these total outcomes, there are only 60 pairs which are sibling pairs. Hence answer is = 60/(800 * 1000) = 3/40000

MBA Acceptance Rate by Application Round Some business schools have roughly the same acceptance rate during all rounds while others see a significant drop off in later rounds. With...

A critical phase of the MBA application, concurrent to researching your target schools, is “researching yourself” and building your profile. What are your unique traits? Where do you want to be...