Leaders and Followers

Expert replies

GmatKiss: Legendary Member; Posts: 2789; Joined: Tue Jul 26, 2011 12:19 amFollowed by: 43 members; Location: Chennai, India; Thanked: 206 times; GMAT Score:640

by GmatKiss » Sat Aug 06, 2011 12:17 pm

At a motivational forum, a group of 1,500 people are separated into two groups, the Leaders and the Followers. 1,000 people are assigned to the Followers and 500 are assigned to the Leaders. Among these people, there are 75 married couples, each consisting of 1 Leader and 1 Follower. If 1 person is chosen randomly from each group, what is the probability that the two people chosen will be a married couple?

3/20000

1/4500

19/1800

1/75

2/225

Like this post

Source: Beat The GMAT — Problem Solving | Sat Aug 06, 2011 12:17 pm

maihuna: Legendary Member; Posts: 1578; Joined: Sun Dec 28, 2008 1:49 amFollowed by: 9 members; Thanked: 82 times; GMAT Score:720

by maihuna » Sat Aug 06, 2011 12:30 pm

it shud be: 75/1000*500 = 3/20000

GmatKiss wrote:At a motivational forum, a group of 1,500 people are separated into two groups, the Leaders and the Followers. 1,000 people are assigned to the Followers and 500 are assigned to the Leaders. Among these people, there are 75 married couples, each consisting of 1 Leader and 1 Follower. If 1 person is chosen randomly from each group, what is the probability that the two people chosen will be a married couple?

3/20000

1/4500

19/1800

1/75

2/225

Charged up again to beat the beast

Like this post

edge: Senior | Next Rank: 100 Posts; Posts: 49; Joined: Sun Jun 26, 2011 5:45 pm; Thanked: 2 times

by edge » Sat Aug 06, 2011 12:31 pm

My answer is A.

P(married leader) = 75/500 = 3/20
P(married follower) = 75/1000
P(particular married follower) = 1/75 (we need this because we have to find the counterpart of the married leader from the followers)

Therefore, P = 3/20 x 75/1000 x 1/75 = 3/20000.

Like this post

ajaykpat: Junior | Next Rank: 30 Posts; Posts: 14; Joined: Mon Jun 13, 2011 8:43 am; Thanked: 1 times

by ajaykpat » Sun Aug 07, 2011 3:07 am

from question we have information that each group consisting of 75 couple members.

If first we choose from Leaders group then probability of selecting couple = 75C1 / 500C1

now , for section of couple partner in Followers group we have only one choice i.e. = 1/ 1000C1

combining both probability = 75C1 x 1/ 1000C1 x 500C1 = [spoiler]3/20000[/spoiler]

Br,

ajp

Like this post

Post new topic Post Reply

• Page 1 of 1

GMAT Course Reviews

563 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (563 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review