Last visit was: 17 Nov 2024, 07:25 It is currently 17 Nov 2024, 07:25

Close

GRE Prep 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 GRE 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.

Close

Request Expert Reply

Confirm Cancel
Verbal Expert
Joined: 18 Apr 2015
Posts: 29963
Own Kudos [?]: 36250 [7]
Given Kudos: 25912
Send PM
Intern
Intern
Joined: 15 Jun 2021
Posts: 23
Own Kudos [?]: 16 [0]
Given Kudos: 23
Send PM
Verbal Expert
Joined: 18 Apr 2015
Posts: 29963
Own Kudos [?]: 36250 [1]
Given Kudos: 25912
Send PM
Manager
Manager
Joined: 23 Sep 2023
Posts: 65
Own Kudos [?]: 13 [1]
Given Kudos: 59
Send PM
Re: For a certain probability experiment, the probability that Event A wil [#permalink]
1
Carcass wrote:
OE

Let us make a table structure for this question:
We are given that, P (A) = 3/4; hence P (A does not occur) = 1 −3/4=1/4
Also, P (B occurs) is given as 1/2
Therefore, P (B does not occur) = 1 −1/2=1/2

We need to find AꓵB; i.e. both A occurs and B occurs.
To find minimum value of AꓵB (𝑥); let us maximize 𝑦.
We know, 𝑥 + 𝑦 =1/2
and 𝑦 + 𝑏 =1/4
The minimum value 𝑏 can have is 0 in that case 𝑦 =1/4

Hence, minimum 𝑥 =1/4
To find maximum value of 𝑥, let us minimize 𝑦.
We know, 𝑥 + 𝑦 =1/2
and 𝑦 + 𝑏 =1/4
The maximum value 𝑏 can have is 1/4 in that case 𝑦 = 0.

Therefore, maximum value of 𝑥 =1/2.
Therefore, AꓵB varies from 1/4 to 1/2.
From the options provided 1/3
is the only value which lies between 1/4 to 1/2

Ans. (C)


This is useful, and can you please mention what is y and what is b?
Verbal Expert
Joined: 18 Apr 2015
Posts: 29963
Own Kudos [?]: 36250 [0]
Given Kudos: 25912
Send PM
For a certain probability experiment, the probability that Event A wil [#permalink]
Expert Reply
Set a possible matrix

A occurs + a does not

B occurs + B does not

Double Matrix
[b]EventsA occursA does not occurResults
B occurs xy1/2
B does not occur ab1/2
Results 3/41/41
Manager
Manager
Joined: 23 Sep 2023
Posts: 65
Own Kudos [?]: 13 [0]
Given Kudos: 59
Send PM
Re: For a certain probability experiment, the probability that Event A wil [#permalink]
test01 wrote:
Carcass wrote:
OE

Let us make a table structure for this question:
We are given that, P (A) = 3/4; hence P (A does not occur) = 1 −3/4=1/4
Also, P (B occurs) is given as 1/2
Therefore, P (B does not occur) = 1 −1/2=1/2

We need to find AꓵB; i.e. both A occurs and B occurs.
To find minimum value of AꓵB (𝑥); let us maximize 𝑦.
We know, 𝑥 + 𝑦 =1/2
and 𝑦 + 𝑏 =1/4
The minimum value 𝑏 can have is 0 in that case 𝑦 =1/4

Hence, minimum 𝑥 =1/4
To find maximum value of 𝑥, let us minimize 𝑦.
We know, 𝑥 + 𝑦 =1/2
and 𝑦 + 𝑏 =1/4
The maximum value 𝑏 can have is 1/4 in that case 𝑦 = 0.

Therefore, maximum value of 𝑥 =1/2.
Therefore, AꓵB varies from 1/4 to 1/2.
From the options provided 1/3
is the only value which lies between 1/4 to 1/2

Ans. (C)


This is useful, and can you please mention what is y and what is b?



I thought about this and have an alternative approach. Carcass please point out if I got it wrong:

P(A) = 3/4 and P(B) = 1/2.
And P(A U B) =1 (at max).
So, 3/4 + 1/2 - x = 1
=> x = 1/4

Now, P( A int B) = 3/4 * 1/2 = 3/8 = 0.375

So, 0.25 <= P(A int B) <= 0.375.
Opt C is the only one fitting in this range.
Verbal Expert
Joined: 18 Apr 2015
Posts: 29963
Own Kudos [?]: 36250 [0]
Given Kudos: 25912
Send PM
Re: For a certain probability experiment, the probability that Event A wil [#permalink]
Expert Reply
yes sir. It is correct as explanation and neat

here a very similar question with a similar solution you provided

https://gmatclub.com/forum/for-a-certai ... 96324.html
Manager
Manager
Joined: 23 Sep 2023
Posts: 65
Own Kudos [?]: 13 [0]
Given Kudos: 59
Send PM
Re: For a certain probability experiment, the probability that Event A wil [#permalink]
Carcass wrote:
yes sir. It is correct as explanation and neat

here a very similar question with a similar solution you provided



thank you so much
Prep Club for GRE Bot
Re: For a certain probability experiment, the probability that Event A wil [#permalink]
Moderators:
GRE Instructor
78 posts
GRE Forum Moderator
37 posts
Moderator
1111 posts
GRE Instructor
234 posts

Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne