BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Probability in Group

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 31
Joined: Sun Oct 16, 2011 10:02 am
Thanked: 4 times
Followed by:3 members

Probability in Group

by gmatNooB8787 » Thu May 03, 2012 2:35 pm
A small company employs 3 men and 5 women. If a team of 4 employees is to be randomly selected to organize the company retreat, what is the probability that the team will have exactly 2 women?
1/14
1/7
2/7
3/7
1/2

solution : total people can be selected in 8C4 ways => 70
The 3 women can be selected in : 5C3 ways => 10
The 2 men can be selected in : 3C2 ways => 3
Hence total ways of selecting : 3*10 = 30

Hence Probability : 30/70 = 3/7.


Is there a different way to solving this problem ? Can anyone tell me what is the best way to solve this problem ?
Top
Source: — Problem Solving |
User avatar
GMAT Instructor
Posts: 1248
Joined: Thu Mar 29, 2012 2:57 pm
Location: Everywhere
Thanked: 503 times
Followed by:192 members
GMAT Score:780

by Bill@VeritasPrep » Thu May 03, 2012 6:36 pm
Two spots for men: 3 choices for the first spot, 2 for the second. 3*2=6, but remember to divide by 2 (since AB and BA are both included) for a total of 3

Two spots for men: 5 choices for the first spot, 4 for the second. 5*4=20, divide by 2 for a total of 10.

3*10=30 groups of 2 men and 2 women

Four spots: 8 choices, 7 choices, 6 choices, 5 choices. Divide by 4!=24, which means you can do 8*7*6*5/24 = 48*7*5/24 = 2*7*5=70

30/70 = 3/7

Not necessarily any faster, though.
Join Veritas Prep's 2010 Instructor of the Year, Matt Douglas for GMATT Mondays

Visit the Veritas Prep Blog

Try the FREE Veritas Prep Practice Test
Top
Post new topic Post Reply
• Page 1 of 1