It is currently 21 Nov 2018, 05:38
My Tests

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.

Probability that at least one of the event occurs is ?

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Intern
Intern
Joined: 19 Mar 2018
Posts: 14
Followers: 0

Kudos [?]: 4 [0], given: 4

Probability that at least one of the event occurs is ? [#permalink] New post 19 Mar 2018, 09:01
00:00

Question Stats:

44% (00:59) correct 55% (00:52) wrong based on 9 sessions
Probability of an event A occurring is 0.2
Probability of an event B occurring is 0.3

What is the range of probabilities that at least one event will occur?
Moderator
Moderator
User avatar
Joined: 18 Apr 2015
Posts: 4928
Followers: 74

Kudos [?]: 982 [0], given: 4518

CAT Tests
Re: Probability that at least one of the event occurs is ? [#permalink] New post 19 Mar 2018, 10:29
Expert's post
Please follow the rules for posting on the board. https://greprepclub.com/forum/rules-for ... -1083.html

Moreover, where are the answer choices ??

Thank you so much for your collaboration.

Regards
_________________

Get the 2 FREE GREPrepclub Tests

1 KUDOS received
Intern
Intern
Joined: 20 Mar 2018
Posts: 34
GRE 1: Q164 V150
Followers: 1

Kudos [?]: 24 [1] , given: 2

Re: Probability that at least one of the event occurs is ? [#permalink] New post 20 Mar 2018, 22:53
1
This post received
KUDOS
Let's say the events are A and B. Essentially, we have to find the range of P(A or B)

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

The maximum probability of occurrence of any one of the events is when the events are mutually exclusive i.e. P (A and B) = 0. So, P(A or B) = 0.2 + 0.3 = 0.5
The minimum probability of occurrence of any one of the events is when the intersection is maximum i.e P(A and B) = 0.2. So, P(A or B) = 0.2 + 0.3 - 0.2 = 0.3

Range: 0.3 to 0.5
Intern
Intern
Joined: 19 Mar 2018
Posts: 14
Followers: 0

Kudos [?]: 4 [0], given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 00:03
So if P(A) = 0.8 and P(B) = 0.7 then max probability is 1.5 ? That doesnt seem right.

Posted from my mobile device Image
1 KUDOS received
Manager
Manager
Joined: 27 Sep 2017
Posts: 112
Followers: 1

Kudos [?]: 29 [1] , given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 00:27
1
This post received
KUDOS
cyanApples wrote:
So if P(A) = 0.8 and P(B) = 0.7 then max probability is 1.5 ? That doesnt seem right.

Posted from my mobile device Image



OK, since you post the question, can you offer the Answer?
Intern
Intern
Joined: 19 Mar 2018
Posts: 14
Followers: 0

Kudos [?]: 4 [0], given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 00:30
Well I'm unsure hence I posted ?

Posted from my mobile device Image
2 KUDOS received
Manager
Manager
Joined: 27 Sep 2017
Posts: 112
Followers: 1

Kudos [?]: 29 [2] , given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 00:31
2
This post received
KUDOS
novice07 wrote:
Let's say the events are A and B. Essentially, we have to find the range of P(A or B)

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

The maximum probability of occurrence of any one of the events is when the events are mutually exclusive i.e. P (A and B) = 0. So, P(A or B) = 0.2 + 0.3 = 0.5
The minimum probability of occurrence of any one of the events is when the intersection is maximum i.e P(A and B) = 0.2. So, P(A or B) = 0.2 + 0.3 - 0.2 = 0.3

Range: 0.3 to 0.5


Though I agree with the maximum, but I have with minimum value. i think we can choose 0.2 NOT 0.3, since we think that at least B occur. then it would be 0.2.

range: 0.2-0.5.
Intern
Intern
Joined: 20 Mar 2018
Posts: 34
GRE 1: Q164 V150
Followers: 1

Kudos [?]: 24 [0], given: 2

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 01:25
Peter wrote:
novice07 wrote:
Let's say the events are A and B. Essentially, we have to find the range of P(A or B)

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

The maximum probability of occurrence of any one of the events is when the events are mutually exclusive i.e. P (A and B) = 0. So, P(A or B) = 0.2 + 0.3 = 0.5
The minimum probability of occurrence of any one of the events is when the intersection is maximum i.e P(A and B) = 0.2. So, P(A or B) = 0.2 + 0.3 - 0.2 = 0.3

Range: 0.3 to 0.5


Though I agree with the maximum, but I have with minimum value. i think we can choose 0.2 NOT 0.3, since we think that at least B occur. then it would be 0.2.

range: 0.2-0.5.

You're correct.

Thanks Peter.
+1 Kudos
4 KUDOS received
Intern
Intern
Joined: 21 Mar 2018
Posts: 1
Followers: 0

Kudos [?]: 4 [4] , given: 0

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 06:26
4
This post received
KUDOS
0.44
Manager
Manager
Joined: 27 Sep 2017
Posts: 112
Followers: 1

Kudos [?]: 29 [0], given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 08:22
oyetundekabiru wrote:
0.44


explain it, thanks

Last edited by Peter on 21 Mar 2018, 08:37, edited 1 time in total.
Manager
Manager
Joined: 27 Sep 2017
Posts: 112
Followers: 1

Kudos [?]: 29 [0], given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 08:25
cyanApples wrote:
Well I'm unsure hence I posted ?

Posted from my mobile device Image



Please give the source of the question.
Intern
Intern
Joined: 19 Mar 2018
Posts: 14
Followers: 0

Kudos [?]: 4 [0], given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 09:31
It's from the actual GRE.

Posted from my mobile device Image
Moderator
Moderator
User avatar
Joined: 18 Apr 2015
Posts: 4928
Followers: 74

Kudos [?]: 982 [0], given: 4518

CAT Tests
Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 15:10
Expert's post
Sorry, could you tell us if this is a quantity comparison question or a multiple answer choice question ??

In the latter, could you provide the 5 answer choices ?'

Thank you for your collaboration. And please, when you post a question, post it in a proper manner and use the tags.

This way, you give a lot of help to the other students and the community as a whole.

Thank you, once again.

Regards
_________________

Get the 2 FREE GREPrepclub Tests

Intern
Intern
Joined: 19 Mar 2018
Posts: 14
Followers: 0

Kudos [?]: 4 [0], given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 18:14
Hi, the question is a multiple choice question. And since It showed up on my GRE , I can't recollect the answer choices correctly. Although I do remember that the answer choices were ranges and one of the choice was 0.5 >= P >= 0.2.

Sorry for incomplete answers.

Posted from my mobile device Image
Intern
Intern
Joined: 20 Mar 2018
Posts: 34
GRE 1: Q164 V150
Followers: 1

Kudos [?]: 24 [0], given: 2

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 21:18
If P(A) = 0.8 and P(B) = 0.7, then Events A and B have to be independent for P(A and B) to be 0. Since they are not (which we assume when not given otherwise) there must be some intersection of these events.
So, if P(A) is 0.8 and P(B) is 0.7 then P(A and B)maximum would be 1, since it can't exceed 1.

Last edited by novice07 on 21 Mar 2018, 23:28, edited 1 time in total.
Intern
Intern
Joined: 19 Mar 2018
Posts: 14
Followers: 0

Kudos [?]: 4 [0], given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 22:23
novice07 wrote:
Events A and B have to be independent for P(A and B) to be 0.

Don't you mean dependent ?

Posted from my mobile device Image
Intern
Intern
Joined: 20 Mar 2018
Posts: 34
GRE 1: Q164 V150
Followers: 1

Kudos [?]: 24 [0], given: 2

Re: Probability that at least one of the event occurs is ? [#permalink] New post 21 Mar 2018, 23:33
No, I mean independent.
If P(A) = 0.7, P(B) = 0.8 and P(A and B)=0 then they must be independent events, which is not the case in this question. If they had given P(A) = 0.7 and P(B) = 0.8 in the question, they would have given certain value for P(A and B) as well.
Manager
Manager
Joined: 27 Sep 2017
Posts: 112
Followers: 1

Kudos [?]: 29 [0], given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 22 Mar 2018, 22:45
novice07 wrote:
No, I mean independent.
If P(A) = 0.7, P(B) = 0.8 and P(A and B)=0 then they must be independent events, which is not the case in this question. If they had given P(A) = 0.7 and P(B) = 0.8 in the question, they would have given certain value for P(A and B) as well.



If P(A) = 0.7, P(B) = 0.8 and P(A and B)=0 then they must be independent events?

no, they are mutually exclusively events, which intersection would not be allowed.
Manager
Manager
Joined: 27 Sep 2017
Posts: 112
Followers: 1

Kudos [?]: 29 [0], given: 4

Re: Probability that at least one of the event occurs is ? [#permalink] New post 22 Mar 2018, 22:48
novice07 wrote:
If P(A) = 0.8 and P(B) = 0.7, then Events A and B have to be independent for P(A and B) to be 0. Since they are not (which we assume when not given otherwise) there must be some intersection of these events.
So, if P(A) is 0.8 and P(B) is 0.7 then P(A and B)maximum would be 1, since it can't exceed 1.



Your concept is weak. For independent events, events are said not to affect each other, but they can both occur.

For example, the tail of a coin can occur with a dice rolling 6.

however, mutually exclusively events would not allow both events to occur, for example the tail and the face of a coin can not both occur.

Also the it is the maximum of (A or B) NOT (A and B) is 1. you should draw 2 circles which one stands for P(A) 0.8, the other stands for P(B) 0.7. Then the maximum of (A and B) is 0.7 when P(B) 0.7 is included in P(A) 0.8.
1 KUDOS received
Intern
Intern
Joined: 20 Mar 2018
Posts: 34
GRE 1: Q164 V150
Followers: 1

Kudos [?]: 24 [1] , given: 2

Re: Probability that at least one of the event occurs is ? [#permalink] New post 23 Mar 2018, 03:47
1
This post received
KUDOS
Peter wrote:
novice07 wrote:
If P(A) = 0.8 and P(B) = 0.7, then Events A and B have to be independent for P(A and B) to be 0. Since they are not (which we assume when not given otherwise) there must be some intersection of these events.
So, if P(A) is 0.8 and P(B) is 0.7 then P(A and B)maximum would be 1, since it can't exceed 1.



Your concept is weak. For independent events, events are said not to affect each other, but they can both occur.

For example, the tail of a coin can occur with a dice rolling 6.

however, mutually exclusively events would not allow both events to occur, for example the tail and the face of a coin can not both occur.

Also the it is the maximum of (A or B) NOT (A and B) is 1. you should draw 2 circles which one stands for P(A) 0.8, the other stands for P(B) 0.7. Then the maximum of (A and B) is 0.7 when P(B) 0.7 is included in P(A) 0.8.


That maximum of P(A or B) NOT (A and B) was an overlook. Sorry for that.

I know that independent events can occur together and in that case P(A and B) would be P(A)*P(B). Appreciate for the example. However, I just meant that P(A or B) can't be equal to 1.5 because if two events having probabilities 0.7 and 0.8, it is not possible to have zero intersection.
Re: Probability that at least one of the event occurs is ?   [#permalink] 23 Mar 2018, 03:47
Display posts from previous: Sort by

Probability that at least one of the event occurs is ?

  Question banks Downloads My Bookmarks Reviews Important topics  

Go to page    1   2    Next  [ 27 posts ] 



GRE Prep Club Forum Home| About| Terms and Conditions and Privacy Policy| GRE Prep Club Rules| Contact

Powered by phpBB © phpBB Group

Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.