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 500,000 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: : What is the probability that event E or event F or both w [#permalink]
18 Mar 2011, 06:05
bogos wrote:
If we agree that 1. (E OR F) means E, or F, or both will occur 2. (E AND F) means both will occur
then we have (see MGMAT Guide 4 page 87)
P(E OR F) = P(E) + P(F) - P(E AND F)
Here P(E AND F) is not given, so the answer is E.
P(E OR F) = P(E) + P(F) - P(E AND F) is true if E and F are dependent events.However if they are independent Events P(E OR F) = P(E) + P(F) .Question does not provide information ..whether E and F are dependent/ independent event ...so it should be E
Re: : What is the probability that event E or event F or both w [#permalink]
18 Mar 2011, 08:00
The formula is always true. MGMAT just clarifies the point by seperating the two cases. In fact, we have: P(E AND F) = 0 if E and F are independent. _________________
Re: : What is the probability that event E or event F or both w [#permalink]
18 Mar 2011, 10:18
Quote:
P(E AND F) = 0 if E and F are independent.
Not true, P(E AND F) = 0 if E and F are MUTUALLY EXCLUSIVE.
To say that E and F are independent means only that the outcome of E has no effect on the outcome of F and vice versa.
Quote:
P(E OR F) = P(E) + P(F) - P(E AND F) is true if E and F are dependent events.However if they are independent Events P(E OR F) = P(E) + P(F)
If they are independent events you still need the -P(E and F)
For example: If you flip two coins (coins 1 and 2) at the same time, and we call the event that coin 1 lands heads "E" and the event the coin 2 lands heads "F", what is P(E or F)?
Ifor example, if two coins are flipped the chance of both being heads is [18]
Mutually exclusive If either event A or event B or both events occur on a single performance of an experiment this is called the union of the events A and B denoted as .
For example, the chance of rolling a 1 or 2 on a six-sided die is
This is from Wikipedia. I found this when I was searching for the explanation for this question. But I am still confused the difference between independent probability and mutually exclusive. To me, they sound the same. Help me understand them.
Re: What is the probability that event E or event F or both will [#permalink]
14 Jan 2014, 01:39
Hello from the GMAT Club BumpBot!
Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).
Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. _________________
Re: What is the probability that event E or event F or both will [#permalink]
28 Jan 2014, 04:22
1
This post received KUDOS
Mountain14 wrote:
Hi Bunuel,
I am not clear why E is the answer...
we have to find P(E)+P(F) + P(EUF), so using Stm1 and Stm 2, we should be able to find.
i.e 0.6 +0.4 + ( 0.6x0.4)...
So, Isn't the answer should be C
Thanks
I'm not Bunuel but I'm sure I can help
P (A and B) = P(A) * P (B/A). That means the probability of B given that A happens. Now only way that the second term is equal to P(B) is if they are independent events, otherwise the probability will be affected. For instance if you have some balls to pick from and you remove some and don't replace them then successive probabilities will change right? So back to the question, Are they independent events? We just don't know this.
Hope it helps brother Cheers! K
PS. Just as a side note check also Mutually exclusive events in the GMAT Club Math Book just to be clear with those Probability concepts
Re: What is the probability that event E or event F or both will [#permalink]
28 Jan 2014, 05:34
Hi we have no information weather E and F are independent events. So we cant answer the question even by considering the two choices So ans should be E
Re: What is the probability that event E or event F or both will [#permalink]
10 Mar 2015, 01:44
Hello from the GMAT Club BumpBot!
Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).
Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email. _________________
You know what’s worse than getting a ding at one of your dreams schools . Yes its getting that horrid wait-listed email . This limbo is frustrating as hell . Somewhere...
As I’m halfway through my second year now, graduation is now rapidly approaching. I’ve neglected this blog in the last year, mainly because I felt I didn’...
Wow! MBA life is hectic indeed. Time flies by. It is hard to keep track of the time. Last week was high intense training Yeah, Finance, Accounting, Marketing, Economics...