It is currently 22 Jan 2018, 00:38

Close

GMAT Club Daily Prep

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.

Close

Request Expert Reply

Confirm Cancel

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Manager
Manager
avatar
Joined: 21 Jul 2003
Posts: 64
Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are [#permalink]

Show Tags

New post 23 Jan 2010, 14:49
3
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

94% (01:12) correct 6% (00:43) wrong based on 49 sessions

HideShow timer Statistics

Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are chosen, one at a time, from the class, what is the probability that a boy and a girl are chosen?

A. 9/48
B. 9/20
C. 11/24
D. 27/48
E. 13/16
[Reveal] Spoiler: OA
Intern
Intern
User avatar
Joined: 21 Jan 2010
Posts: 49
Location: Canada
Re: Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are [#permalink]

Show Tags

New post 23 Jan 2010, 15:03
prasadrg wrote:
Mr. Yutaro’s class contains 5boys and 11 girls. If two students are chosen, one at a time, from the class, what is
the probability that a boy and a girl are chosen?
A. 9/48
B. 9/20
C. 11/24
D. 27/48
E. 13/16


Probability of a boy being chosen first, then a girl:
5/16 * 11/15

Probability of a girl being chosen first, then a boy:
11/16 * 5/15

Probability of a boy and a girl being chosen:
(5*11+5*11) / (15*16)
=11+11/3*16
=22/48
=11/24, so C.
_________________

________________________________________________________________________
Andrew
http://www.RenoRaters.com

Intern
Intern
avatar
Joined: 15 Oct 2007
Posts: 9
Location: India
Re: Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are [#permalink]

Show Tags

New post 19 Feb 2010, 04:40
(5C1*11C1)/16C2 = 11/24
Senior Manager
Senior Manager
User avatar
Joined: 21 Jul 2009
Posts: 364
Schools: LBS, INSEAD, IMD, ISB - Anything with just 1 yr program.
Re: Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are [#permalink]

Show Tags

New post 19 Feb 2010, 11:24
1
This post was
BOOKMARKED
umeshkathuria wrote:
(5C1*11C1)/16C2 = 11/24


Actually, problems of this kind, prefer subtracting from all possible probabilities = 1.

Subtract probability of choosing only two boys and probability of choosing only two girls and that should give the final answer. This will be more helpful when you have many more selections that happen and not just 2 and one from each is required.
_________________

I am AWESOME and it's gonna be LEGENDARY!!!

Senior Manager
Senior Manager
avatar
Joined: 01 Feb 2010
Posts: 251
Re: Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are [#permalink]

Show Tags

New post 20 Feb 2010, 07:39
prasadrg wrote:
Mr. Yutaro’s class contains 5boys and 11 girls. If two students are chosen, one at a time, from the class, what is
the probability that a boy and a girl are chosen?
A. 9/48
B. 9/20
C. 11/24
D. 27/48
E. 13/16


Ways to choose one boy = 5c1 = 5
Ways to choose one girl = 11c1 = 11

Total ways = 16c2 = 16*15

p=(5*11)/16*15 - 11/24 hence C
Expert Post
Top Contributor
SVP
SVP
User avatar
P
Joined: 11 Sep 2015
Posts: 1999
Location: Canada
Re: Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are [#permalink]

Show Tags

New post 28 Dec 2017, 15:32
Expert's post
Top Contributor
prasadrg wrote:
Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are chosen, one at a time, from the class, what is the probability that a boy and a girl are chosen?

A. 9/48
B. 9/20
C. 11/24
D. 27/48
E. 13/16


P(1 boy and 1 girl chosen) = P(1st selection is boy AND 2nd selection is girl OR 1st selection is girl AND 2nd selection is boy)
= P(1st selection is boy AND 2nd selection is girl) + P(1st selection is girl AND 2nd selection is boy)
= P(1st selection is boy) x P(2nd selection is girl) + P(1st selection is girl) x P(2nd selection is boy)
= 5/16 x 11/15 + 11/16 x 5/15
= 55/240 + 55/240
= 110/240
= 11/24
= C

Cheers,
Brent
_________________

Brent Hanneson – Founder of gmatprepnow.com

Image

Manager
Manager
avatar
B
Joined: 23 Oct 2017
Posts: 63
Re: Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are [#permalink]

Show Tags

New post 28 Dec 2017, 18:10
Number of ways of selecting two students from the class of 5 boys & 11 girls = 16C2 (total) =15*16/2
Number of ways of selecting 1 boy & 1 girl = 5C1 * 11C1 = 5*11
probability = 5*11/15*8 = 11/24
Re: Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are   [#permalink] 28 Dec 2017, 18:10
Display posts from previous: Sort by

Mr. Yutaro’s class contains 5 boys and 11 girls. If two students are

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  


GMAT Club MBA Forum Home| About| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.