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.

It appears that you are browsing the GMAT Club forum unregistered!

Signing up is free, quick, and confidential.
Join other 350,000 members and get the full benefits of GMAT Club

Registration gives you:

Tests

Take 11 tests and quizzes from GMAT Club and leading GMAT prep companies such as Manhattan GMAT,
Knewton, and others. All are free for GMAT Club members.

Applicant Stats

View detailed applicant stats such as GPA, GMAT score, work experience, location, application
status, and more

Books/Downloads

Download thousands of study notes,
question collections, GMAT Club’s
Grammar and Math books.
All are free!

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Re: Probability of 2 actresses being chosen together from 5 [#permalink]
02 Dec 2010, 04:51

2

This post received KUDOS

Expert's post

ViG wrote:

5 a list actresses are vying for 3 spots. J, M, S, L and H. What is the probability that J and H will star in the film together?

\(Probability=\frac{# \ of \ favorable \ outcomes}{total \ # \ of \ outcomes}\).

Now, total # of outcomes will be \(C^3_5=10\), (# of ways to choose 3 different actresses out of 5 when order of selection doesn't matter);

As for the # of favorable outcomes: we want 2 places out of 3 to be taken be J and H: so {JH-?}, for the third spot we can choose ANY from the 3 actresses left M, S, L. So, there are 3 such favorable groups possible: {JH-M}, {JH-S}, {JH-L}. Or \(C^1_1*C^1_3\), where \(C^1_1=1\) is 1 way to choose J and H (as it's one group) and \(C^1_3=3\) is 3 ways to choose the third member;

Re: Probability of 2 actresses being chosen together from 5 [#permalink]
04 Dec 2010, 17:03

Expert's post

ViG wrote:

ok, I got it.

It's not 5c3 as order matters so it's in fact 5!/3! which yields 6/20 = 3/10

It's pretty simple. Think of it as an arrangement, really.

The ways in which you can get those two acting together can be done in three ways, depending on who the third actress is. The ways in which you can pick any three actresses is 5C3. Hence 3/5C3 = 3/10 is the answer.

Re: Probability of 2 actresses being chosen together from 5 [#permalink]
13 Feb 2011, 08:59

How about this:

since the order doesn't matter the probability of any actress to be selected on any spot is 3/5. (in other words ANY actress has 3/5 chance to be selected) Next, we have 2 spots with 4 actresses, which gives us 2/4=1/2 probability of any given actress to be selected. Now, we just multiply probabilities 3/5 * 1/2 = 3/10. this might be a shortcut.

Re: Probability of 2 actresses being chosen together from 5 [#permalink]
11 Sep 2011, 00:12

whiplash2411 wrote:

ViG wrote:

ok, I got it.

It's not 5c3 as order matters so it's in fact 5!/3! which yields 6/20 = 3/10

It's pretty simple. Think of it as an arrangement, really.

The ways in which you can get those two acting together can be done in three ways, depending on who the third actress is. The ways in which you can pick any three actresses is 5C3. Hence 3/5C3 = 3/10 is the answer.

i dont get why do we divide 3 / 10 ?? why is 10 in the denominator?

Re: Probability of 2 actresses being chosen together from 5 [#permalink]
11 Sep 2011, 00:20

siddhans wrote:

whiplash2411 wrote:

ViG wrote:

ok, I got it.

It's not 5c3 as order matters so it's in fact 5!/3! which yields 6/20 = 3/10

It's pretty simple. Think of it as an arrangement, really.

The ways in which you can get those two acting together can be done in three ways, depending on who the third actress is. The ways in which you can pick any three actresses is 5C3. Hence 3/5C3 = 3/10 is the answer.

i dont get why do we divide 3 / 10 ?? why is 10 in the denominator?

P=Favorable Outcome/Total outcome Total outcome= Number of ways to choose any 3 actresses out of 5= \(C^5_3=\frac{5!}{3!(5-3)!}=\frac{5!}{3!2!}=10\) Thus, denominator is 10.

Numerator=3, because there are only 3 favorable outcomes: JHM JHS JHL _________________

How the growth of emerging markets will strain global finance : Emerging economies need access to capital (i.e., finance) in order to fund the projects necessary for...

Good news for globetrotting MBAs: travel can make you a better leader. A recent article I read espoused the benefits of traveling from a managerial perspective, stating that it...