Question of the Day - 25th August, 2009

This topic has expert replies
Senior | Next Rank: 100 Posts
Posts: 74
Joined: Fri Jul 31, 2009 11:38 am
Thanked: 4 times
Followed by:1 members

Question of the Day - 25th August, 2009

by quant-master » Mon Aug 24, 2009 3:28 pm
Question 1:

What is the probability for a family with three children to have a boy and two girls, assuming the probability of having a boy or a girl is equal?

a)1/8
b)¼
c)½
d)3/8
e)5/8

OAs will be posted in 24 hrs time

Thanks,
Quant-Master
https://gmat-quants.blocked - My Blog Updated almost daily with new quant fundas. Find collection of quants question in my blog

Junior | Next Rank: 30 Posts
Posts: 10
Joined: Tue May 06, 2008 10:44 pm
Thanked: 1 times

by keough » Mon Aug 24, 2009 3:33 pm
Let P(B) = P(G) = 1/2

so, 1 Boy and 2 girls can be

1. B,G,G = 1/2*1/2*1/2 = 1/8
2. G,B,G = 1/8
3. G,G,B = 1/8

P(B and 2 Gs) = 1/8 + 1/8 + 1/8 = 3/8

Senior | Next Rank: 100 Posts
Posts: 74
Joined: Fri Jul 31, 2009 11:38 am
Thanked: 4 times
Followed by:1 members

by quant-master » Tue Aug 25, 2009 3:48 pm
That's correct.

D is the right answer.

Let me know if anybody needs further explanation

Thanks,
Quant-Master
https://gmat-quants.blocked - My Blog Updated almost daily with new quant fundas. Find collection of quants question in my blog