• Magoosh
Study with Magoosh GMAT prep

Available with Beat the GMAT members only code

• Get 300+ Practice Questions

Available with Beat the GMAT members only code

• Free Trial & Practice Exam
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• 1 Hour Free
BEAT THE GMAT EXCLUSIVE

Available with Beat the GMAT members only code

• Free Practice Test & Review
How would you score if you took the GMAT

Available with Beat the GMAT members only code

• 5-Day Free Trial
5-day free, full-access trial TTP Quant

Available with Beat the GMAT members only code

• Free Veritas GMAT Class
Experience Lesson 1 Live Free

Available with Beat the GMAT members only code

• 5 Day FREE Trial
Study Smarter, Not Harder

Available with Beat the GMAT members only code

• Award-winning private GMAT tutoring
Register now and save up to \$200

Available with Beat the GMAT members only code

tagged by: Brent@GMATPrepNow

This topic has 3 expert replies and 4 member replies
Aman verma Master | Next Rank: 500 Posts
Joined
27 Jan 2010
Posted:
304 messages
Followed by:
3 members
Thanked:
11 times

Sat Nov 30, 2013 5:36 am
Elapsed Time: 00:00
• Lap #[LAPCOUNT] ([LAPTIME])
Q:In the upcoming Delhi Elections only two major parties are fighting the elections-The Aam-Aadmi Party headed by Arvind kejriwal and The Aam-Aurat party headed by Dr. Sanjay HarshaVardan. 45% of the population support the Aam-Aadmi Party and 30% of the population support The Aam-Aurat Party and 20% of the population support both the parties. One citizen is selected at random from the population named Aman Verma. Find the probability that he supports the Aam-Admi party if it is known that he supports the Aam-Aurat Party. [Edited: Missing information inserted at the end of the third line]

(A)1/3

(B)2/3

(C)5/6

(D)4/7

(E)5/9

_________________
800. Arjun's-Bird-Eye

Last edited by Aman verma on Sat Nov 30, 2013 9:05 am; edited 1 time in total

Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!

### GMAT/MBA Expert

Brent@GMATPrepNow GMAT Instructor
Joined
08 Dec 2008
Posted:
10763 messages
Followed by:
1212 members
Thanked:
5146 times
GMAT Score:
770
Sat Nov 30, 2013 8:09 am
Aman verma wrote:
Q:In the upcoming Delhi Elections only two major parties are fighting the elections-The Aam-Aadmi Party headed by Arvind kejriwal and The Aam-Aurat party headed by Dr. Sanjay HarshaVardan. 45% of the population support the Aam-Aadmi Party and 30% of the population support The Aam-Aurat Party. One citizen is selected at random from the population named Aman Verma. Find the probability that he supports the Aam-Admi party if it is known that he supports the Aam-Aurat Party.

(A)1/3
(B)2/3
(C)5/6
(D)4/7
(E)5/9
Hi Aman,

As it stands, there is not enough information to answer this question.

Cheers,
Brent

_________________
Brent Hanneson – Founder of GMATPrepNow.com
Use our video course along with

Check out the online reviews of our course
Come see all of our free resources

GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!
Aman verma Master | Next Rank: 500 Posts
Joined
27 Jan 2010
Posted:
304 messages
Followed by:
3 members
Thanked:
11 times
Sat Nov 30, 2013 9:09 am
Brent@GMATPrepNow wrote:
Hi Aman,

As it stands, there is not enough information to answer this question.

Cheers,
Brent
Hi Brent,

Yes, there was an information missing at the end of the third line, which I have inserted in the original post.I was unable to highlight the missing part as I don't know how to do that. Regret the error.

_________________
800. Arjun's-Bird-Eye

Joined
06 May 2013
Posted:
15 messages
Sat Nov 30, 2013 9:48 am
What was the answer? And did they wrote an explanation ?

### GMAT/MBA Expert

Brent@GMATPrepNow GMAT Instructor
Joined
08 Dec 2008
Posted:
10763 messages
Followed by:
1212 members
Thanked:
5146 times
GMAT Score:
770
Sat Nov 30, 2013 10:03 am
Aman verma wrote:
Q:In the upcoming Delhi Elections only two major parties are fighting the elections-The Aam-Aadmi Party headed by Arvind kejriwal and The Aam-Aurat party headed by Dr. Sanjay HarshaVardan. 45% of the population support the Aam-Aadmi Party and 30% of the population support The Aam-Aurat Party and 20% of the population support both the parties. One citizen is selected at random from the population named Aman Verma. Find the probability that he supports the Aam-Admi party if it is known that he supports the Aam-Aurat Party.

(A)1/3
(B)2/3
(C)5/6
(D)4/7
(E)5/9
We can solve this question using the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it.
Here, we have a population of voters, and the two characteristics are:
- pro Aam-Aurat or not pro Aam-Aurat

Since the question does not ask us to find specific numbers of voters, we can assign a "nice" value to the entire population. Let's say that there are 100 voters altogether.

So, we can set up our diagram as follows:

45% of the population support the Aam-Aadmi Party and 30% of the population support The Aam-Aurat Party
We can add this information to our diagram.

20% of the population support both the parties
We'll add that information as well.

At this point, we can determine the number of voters in each box.

Find the probability that he supports the Aam-Aadmi party if it is known that he supports the Aam-Aurat Party.

So, Aman verma is one of the 30 Aam-Aurat supporters.
Of the 30 Aam-Aurat supporters, 20 also support Aam-Aadmi
So, the required probability = 20/30 = 2/3 = B

---------------------------------------------

Here are some additional practice questions that can be solved using the Double Matrix Method:
- http://www.beatthegmat.com/mba/2011/05/05/random-double-matrix-question-1
- http://www.beatthegmat.com/mba/2011/05/09/random-double-matrix-question-2
- http://www.beatthegmat.com/mba/2011/05/16/random-double-matrix-question-3
- http://www.beatthegmat.com/ds-quest-t187706.html
- http://www.beatthegmat.com/overlapping-sets-questions-t183320.html
- http://www.beatthegmat.com/finance-majors-non-finance-majors-overlapping-set-question-t167425.html
- http://www.beatthegmat.com/ds-french-japanese-t222297.html
- http://www.beatthegmat.com/sets-t269449.html#692540
- http://www.beatthegmat.com/in-costume-for-halloween-t269355.html#692116

Cheers,
Brent

_________________
Brent Hanneson – Founder of GMATPrepNow.com
Use our video course along with

Check out the online reviews of our course
Come see all of our free resources

Last edited by Brent@GMATPrepNow on Sat Nov 30, 2013 11:50 am; edited 1 time in total

GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!
Aman verma Master | Next Rank: 500 Posts
Joined
27 Jan 2010
Posted:
304 messages
Followed by:
3 members
Thanked:
11 times
Sat Nov 30, 2013 11:15 am
OA(B)2/3.

Good Night!

_________________
800. Arjun's-Bird-Eye

### GMAT/MBA Expert

Brent@GMATPrepNow GMAT Instructor
Joined
08 Dec 2008
Posted:
10763 messages
Followed by:
1212 members
Thanked:
5146 times
GMAT Score:
770
Sat Nov 30, 2013 11:52 am
Ha - after all of that work, I didn't interpret my own diagram correctly
I edited the last sentence accordingly.

Cheers,
Brent

_________________
Brent Hanneson – Founder of GMATPrepNow.com
Use our video course along with

Check out the online reviews of our course
Come see all of our free resources

GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!
telberrak Newbie | Next Rank: 10 Posts
Joined
19 Apr 2011
Posted:
7 messages
Thanked:
1 times
Test Date:
ASAP
Target GMAT Score:
760
Fri May 16, 2014 1:27 am
Event B : pro Aam-Aurat

pick up a pro Aam-Aadmi knowing he's a pro Aam-Aurat is P(A|B)

Probability of A knowing B (non-independent events) is P(A|B) = P(A and B)/P(B)
P(A and B) = 20%
P(B) = 30%

==> P(A|B) = 20%/30% = 2/3

### Best Conversation Starters

1 Vincen 180 topics
2 lheiannie07 65 topics
3 Roland2rule 49 topics
4 ardz24 40 topics
5 LUANDATO 16 topics
See More Top Beat The GMAT Members...

### Most Active Experts

1 Brent@GMATPrepNow

GMAT Prep Now Teacher

146 posts
2 Rich.C@EMPOWERgma...

EMPOWERgmat

103 posts
3 GMATGuruNY

The Princeton Review Teacher

100 posts
4 EconomistGMATTutor

The Economist GMAT Tutor

92 posts
5 Jay@ManhattanReview

Manhattan Review

79 posts
See More Top Beat The GMAT Experts