Probability of Passing a Final if You Know Nothing

GMAT Guild Daily Prep

Cheers for using the timer - this advanced tool can estimate your performance and advise more practice questions. Nosotros accept subscribed y'all to Daily Prep Questions via electronic mail.

Customized
for You

nosotros will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we'll ship you lot an estimated GMAT score based on your performance

Practice
Pays

we will selection new questions that friction match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No trouble, unsubscribe here.

• 

  Mar 11

  Part 2 - A crazy GMAT fit for Charity - a Non-Stop Complete GMAT Course in 24 hours in Support of Ukraine! GMAT Ninja will be on air non-stop educational activity a complete crash-course for all skill levels.

• 

  Mar 12

  Did you know 85% of the RC questions are inference based? Learn the Art of Involved & Evolved Reading and brand sure y'all never get an RC question wrong again!

• 

  Mar 12

  Learn the BIGGEST Underground that can help you plow your GMAT prep into a addiction as simple as brushing your teeth with this 4-office program. Unlock your access before this serial is gone for good!

• 

  Mar 12

  2000+ gratuitous GMAT videos | 20+ app aid videos | fifteen+ interview prep videos

• 

  Mar 13

  Strategizing for the exam is every bit important equally preparing for it. Attend this webinar by GMAT Strategy Expert – Piyush, to understand how the GMAT algorithm works and go insights every bit to how you lot can apply the algorithm to your advantage.

• 

  Mar 13

  Attend this costless geometry webinar to learn to visualize the solution, heighten comprehension and solve 700-level geometry questions in Quant with ease.

• 

  Mar 13

  Strategies and techniques for approaching featured GMAT topics. Ane 60 minutes of alive, online didactics

• 

  Mar 16

  ou'll get a free, full-length GMAT practice test, our free Foundations of Math eBook and workshop, and access to free lessons on Sentence Correction and Data Sufficiency.

• 

  Mar 17

  This Th GMAT Social club Tests will be - Absolutely Free! Including all the Quizzes, Questions, and Tests. 12 AM - 11:59 PM PDT

• 

  Mar 17

  In each webinar, nosotros teach game-changing techniques and strategies for solving some of the most loftier-value GMAT quant questions. In addition, we will provide you with the opportunity to ask questions regarding how to best prepare for the GMAT.

• 

  Mar 17

  Video explanations + diagnosis of 10 weakest areas + i-week access to 10 SC e-books and 200 short videos!

• 

  Mar xviii

  Bring together TTP for a GMAT Verbal webinar every Friday at xi:00 AM ET. Marty Murray, who scored a perfect 800 on the GMAT, will host the live session. Following the webinar, you can take part in a Q&A session.

Math Expert

Joined: 02 Sep 2009

Posts: 84690

A student is to take her final exams in two subjects. The probability [#permalink]   05 December 2014, 06:43

00:00

Question Stats:

35% (01:23) right 65% (01:24) wrong based on 266 sessions

Hide Show timer Statistics

Tough and Tricky questions: Probability.

A educatee is to take her concluding exams in two subjects. The probability that she volition pass the first bailiwick is 3/four and the probability that she volition laissez passer the second discipline is ii/3. What is the probability that she will laissez passer one test or the other examination?

A) v/12
B) i/two
C) 7/12
D) 5/7
Due east) 11/12

Kudos for a correct solution.

Source: Chili Hot GMAT

_________________

Intern

Joined: thirteen Sep 2014

Status:Amat Victoria Curam

Posts: 24

Location: India

Re: A student is to have her final exams in two subjects. The probability [#permalink]   05 December 2014, 07:thirty

Let the two subjects be X (probability of passing iii/4) and Y (probability of passing ii/3)
The probability of passing in 10 only is three/four times i/3 (failing in Y) = 1/4
The probability of passing in Y only is 2/3 times 1/4 (failing in 10) = i/6
Therefore the full probability = 1/iv + 1/6 = 5/12

Hence A

Director

Joined: 12 Sep 2014

Posts: 134

Concentration: Strategy, Leadership

GPA: 3.94

Re: A student is to take her last exams in two subjects. The probability [#permalink]   05 Dec 2014, 09:27

We need to compute two different probabilities here--the probability that she passes the first exam and fails the 2d examination and the probability that she passes the 2d exam and fails the first examination. The probability of declining an exam is i - the probability of passing the exam. Then sum the probabilities for your answer:

P = 3/4*1/3 + 1/4*2/iii = 1/4 + ane/6 = five/12

Choice A

Intern

Joined: 02 Apr 2013

Affiliations: University of texas at

Posts: 28

Location: Bangladesh

GMAT 1: 640 Q48 V30

GMAT two: 710 Q49 V37

We:Enquiry (Consumer Products)

Re: A student is to accept her final exams in two subjects. The probability [#permalink]   05 Dec 2014, 17:40

Exercise we really know that P(x) means merely passing in x? If we visualize the venn diagram, P(ten) means probability of passing in x along with yand without y!
My respond would be: 1/iii+ane/4-ane/3*1/4=11/12
This is P(XUY).
Answer Eastward.

Intern

Joined: 02 Apr 2013

Affiliations: University of texas at

Posts: 28

Location: Bangladesh

GMAT 1: 640 Q48 V30

GMAT 2: 710 Q49 V37

We:Enquiry (Consumer Products)

Re: A educatee is to take her final exams in two subjects. The probability [#permalink]   05 Dec 2014, 17:43

Do we really know that P(10) ways only passing in x? If we visualize the venn diagram, P(ten) ways probability of passing in x along with yand without y!
My answer would exist: i/3+1/4-1/3*1/4=11/12
This is P(XUY).
Answer Eastward.

Intern

Joined: xiii Sep 2014

Status:Amat Victoria Curam

Posts: 24

Location: Bharat

Re: A student is to take her final exams in ii subjects. The probability [#permalink]   05 Dec 2014, 18:42

Hi farzana87,

Probabilities are given for P(x) equally a unmarried consequence; and not in conjunction to any other result. So when y'all try to put it in a venn diagram yous are actually trying to find out the parts xNOTy + yNOTx.

nb: Venn diagrams may not be the all-time way to help you with such problems! Bujhle?

Intern

Joined: 02 Apr 2013

Affiliations: Academy of texas at

Posts: 28

Location: Bangladesh

GMAT 1: 640 Q48 V30

GMAT 2: 710 Q49 V37

Nosotros:Research (Consumer Products)

Re: A student is to take her final exams in two subjects. The probability [#permalink]   05 Dec 2014, 22:51

Yes I plant out that P(XUY) ways passing in one or 2 subjects. omegacube

Manager

Joined: 04 October 2013

Posts: 145

Location: India

GMAT Date: 05-23-2015

GPA: 3.45

Re: A pupil is to take her final exams in two subjects. The probability [#permalink]   06 Dec 2014, 00:57

A student is to take her last exams in ii subjects. The probability that she will laissez passer the beginning subject is iii/4 and the probability that she will pass the second subject is 2/iii. What is the probability that she will pass one test or the other exam?

A) 5/12
B) 1/2
C) seven/12
D) 5/7
E) eleven/12

Probability that the student will laissez passer the get-go subject is 3/4 -> Probability that she volition fail in the first discipline is 1/iv
Probability that she volition laissez passer the second discipline is ii/3 -> Probability that she will neglect in the second field of study is ane/3

Probability that she will pass one exam OR the other exam
=Probability that she will pass the offset subject AND neglect in the second subject field + Probability that she will pass the second subject AND fail in the first subject

= \((\frac{3}{4})(\frac{one}{3}) + (\frac{one}{four})(\frac{ii}{3}) =\frac{i}{4}+ \frac{1}{6} = \frac{five}{12}\)

Respond: A

Manager

Joined: 25 Feb 2010

Posts: 234

Re: A pupil is to take her final exams in two subjects. The probability [#permalink]   06 December 2014, 11:04

answer should be A.

---- pass fail
1: 3/4 one/4
2: two/3 ane/3

3/four*i/3 + 2/3*ane/4

=5/12
_________________

GGG (Gym / GMAT / Girl) -- Be Serious

Its your duty to postal service OA afterwards; some 1 must be waiting for that...

Manager

Joined: 13 Jun 2013

Posts: 238

Re: A educatee is to accept her last exams in two subjects. The probability [#permalink]   06 Dec 2014, 12:21

This question can also exist solved by using venn diagram.

As prove in the figure above. the required probability is the highlighted surface area in reddish. permit circle A represents probability of passing in outset exam =3/four, and circle B represents probability of passing in 2d exam = 2/3 and the probability of passing in both the exams = (2/iii)(three/4) = 1/two

thus highlighted portion on the left paw side can exist calculated as 3/4-i/ii = ane/iv
highlighted portion on the right mitt side tin can be calculated every bit 2/3-one/ii = ane/6

thus required probability is 1/4+1/6 = 5/12

Manager

Joined: 04 October 2013

Posts: 145

Location: India

GMAT Engagement: 05-23-2015

GPA: three.45

Re: A educatee is to take her final exams in two subjects. The probability [#permalink]   06 Dec 2014, 21:18

A student is to have her final exams in two subjects. The probability that she will pass the kickoff subject field is 3/four and the probability that she volition pass the second subject is 2/three. What is the probability that she will pass one exam or the other exam?

Alternate Solution (Table Method)

Attachments

Probability-Table-Method.png [ 12.38 KiB | Viewed 15573 times ]

Manager

Joined: eleven Sep 2013

Posts: 109

Concentration: Finance, Finance

Re: A student is to take her concluding exams in two subjects. The probability [#permalink]   18 Mar 2015, 11:01

(iii/4 +2/3)-3/iv*2/iii = 11/12

Intern

Joined: 28 May 2014

Posts: one

Location: Mexico

Concentration: International Business, General Management

Re: A pupil is to take her last exams in 2 subjects. The probability [#permalink]   xviii Mar 2015, 20:56

In probability for multiple event experiments, the probability for A or B is the following:

P(A)+P(B)-P(A and B)

Then we substitute the data from the question:

3/4 + ii/3 - (iii/iv * 2/three) = 17/12 - half dozen/12 = 11/12

Answer is E

Manager

Joined: 22 Jan 2014

Posts: 146

Nosotros:Project Management (Computer Hardware)

Re: A student is to take her final exams in ii subjects. The probability [#permalink]   19 Mar 2015, 06:07

Bunuel wrote:

Bunuel wrote:

Tough and Catchy questions: Probability.

A student is to accept her final exams in two subjects. The probability that she will pass the showtime subject is iii/4 and the probability that she will pass the second discipline is two/3. What is the probability that she will pass ane exam or the other exam?

A) 5/12
B) 1/2
C) 7/12
D) v/7
E) 11/12

Kudos for a correct solution.

Source: Chili Hot GMAT

The correct answer is E.

Hi Bunuel

can you pl let me know where am I going incorrect? i got vii/12. please refer to the epitome...

i got i/3 + 1/4 = 7/12

is this considering i am because that failing in both is not an option?

Attachments

Capture.PNG [ half-dozen.38 KiB | Viewed 15213 times ]

_________________

Illegitimi non carborundum.

Board of Directors

Joined: 17 Jul 2014

Posts: 2273

Location: United States (IL)

Concentration: Finance, Economic science

GMAT i: 650 Q49 V30

GPA: 3.92

We:General Direction (Transportation)

Re: A student is to have her final exams in ii subjects. The probability [#permalink]   19 Mar 2015, 06:20

this is a typical question that "begs" you to identify the probability of not passing either of the exams.
In this particular case, the probability of not passing the start exam is 1/four. The probability of not passing the second exam is 1/3.
The probability of non passing both of the exams is thus equal to (1/4) * (one/3) = 1/12
We tin can then deduct one/12 from one, and we volition get 11/12. This is the probability of passing at least i examination

Intern

Joined: 23 Jul 2013

Posts: xi

Re: A student is to accept her concluding exams in 2 subjects. The probability [#permalink]   19 Mar 2015, 18:49

I derived the answer every bit follows:

P(A or B) = P(A) + P(B) - P(A and B)
P(A or B) = 3/4 + 2/3 - 1/2
P(A or B) = 11/12

Whatsoever suggestions on the correctness of approach? Delight guide.

EMPOWERgmat Instructor

Joined: 19 Dec 2014

Status:GMAT Assassinator/Co-Founder

Affiliations: EMPOWERgmat

Posts: 20319

Location: United states of america (CA)

Re: A student is to accept her final exams in two subjects. The probability [#permalink]   19 Mar 2015, xix:twenty

Howdy All,

The "intent" of this question is not perfectly articulate from the wording.

IF the intent is to ask....what is the probability of passing JUST Ane test, then the answer is v/12.

IF the intent is to ask....what is the probability of passing AT To the lowest degree ONE test, then the answer is xi/12.

The diverse approaches for those solutions take already been presented by other posters, so I won't rehash any of that math here. The Official GMAT writes (and tests out) information technology's questions so that the meaning is clear and in that location is no 'interpretational bias.', so Test Takers won't left to question what the prompt actually asks for.

GMAT assassins aren't born, they're made,
Rich
_________________

Senior Manager

Joined: 24 Nov 2015

Posts: 434

Location: U.s. (LA)

Re: A student is to accept her last exams in 2 subjects. The probability [#permalink]   21 May 2016, 12:35

EMPOWERgmatRichC wrote:

Howdy All,

The "intent" of this question is not perfectly clear from the wording.

IF the intent is to ask....what is the probability of passing Simply One test, then the reply is 5/12.

IF the intent is to inquire....what is the probability of passing AT To the lowest degree One exam, then the answer is xi/12.

The various approaches for those solutions accept already been presented by other posters, so I won't rehash any of that math here. The Official GMAT writes (and tests out) it's questions so that the significant is articulate and at that place is no 'interpretational bias.', so Test Takers won't left to question what the prompt actually asks for.

GMAT assassins aren't born, they're fabricated,
Rich

I too had the aforementioned doubt when solving the question. Dubiety is that whether information technology is request that the student passes EXACTLY one exam and then the answer would exist 5/12 or the student needs to pass at least 1 of the exams in which case the reply is 11/12
I think the question stem is request for first arroyo but wonder why the correct reply is given for latter approach

VP

Joined: 07 Dec 2014

Posts: 1147

Re: A educatee is to accept her concluding exams in ii subjects. The probability [#permalink]   22 May 2016, xi:42

probability of passing neither=(1/three)(1/4)=1/12
probability of passing either=1-1/12=eleven/12

Intern

Joined: 13 Aug 2018

Posts: 8

Location: India

A student is to take her final exams in two subjects. The probability [#permalink]   20 Apr 2021, 12:05

MUTUALLY INDEPENDENT Event

P(a or b) = P(a) + P(b) - P(a&B)

here, P(a) = iii/four
P(b) = 2/3
P(a & b) = P(b)*P(a) = 2/3*3/iv = one/2

P(a or b) = 3/4 + 2/3 - 1/ii = 11/12

Hence, oprtion E

A student is to accept her final exams in two subjects. The probability [#permalink]

20 April 2021, 12:05

Moderators:

Senior Moderator - Masters Forum

2893 posts

Senior SC Moderator

5318 posts

burnshowner.blogspot.com

Source: https://gmatclub.com/forum/a-student-is-to-take-her-final-exams-in-two-subjects-the-probability-189586.html

Share this post