Solve Probability Problem: Find P(B) & P(A/B)

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Homework Help Overview

The problem involves calculating probabilities related to events A and B, specifically finding P(B) and P(A/B) given certain conditional probabilities: P(A/B) = 0.8, P(B/A') = 0.6, and P(A) = 0.75. The context is rooted in probability theory.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the relationships between the given probabilities and how to manipulate them to find the unknowns. There are attempts to clarify the definitions and the relationships between P(A/B), P(A ∩ B), and P(B).

Discussion Status

Participants are actively engaging with the problem, questioning the necessity of calculating certain probabilities, and exploring different interpretations of the given information. Some guidance has been offered regarding the calculation of P(A ∩ B) and P(A' ∩ B) as potential steps forward.

Contextual Notes

There is a noted confusion regarding the terms and the items that need to be calculated, with some participants clarifying the definitions and relationships involved in the problem setup.

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Homework Statement

## The question is as follows given ##P(A/B)=0.8, P(B/A")=0.6## and P(A)=0.75 then find P(B) and ## P(A/B)##[/B]

Homework Equations

The Attempt at a Solution


##P(A/B)= P(AnB)/P(B) ## where## P(AnB)= P(B/A).P(A)= 0.8*0.75=0.6##
##P(A/B)= 0.6/P(B)## am now stuck here how do i move from here?
 
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chwala said:

Homework Statement

[/B]
Given ##P(A/B)=0.8, P(B/A')=0.6## and ##P(A)=0.75## then find ##P(B)## and ## P(A/B)##

Homework Equations

The Attempt at a Solution


##P(A/B)= P(A\land B)/P(B) ## where ## P(A\land B)= P(B/A)P(A)= 0.8*0.75=0.6##
##P(A/B)= 0.6/P(B)## am now stuck here how do i move from here?

looks like you're nearly there... calculate ## p(A') ##, then can you find ## p(A' \land B)## ?
 
If you are given P(A \mid B) why do you need to calculate it?

To be clear: are these the items you are given and the items you are to find?
<br /> \begin{align*}<br /> P(A \mid B) &amp; = 0.8 \\<br /> P(B \mid A&#039;) &amp; = 0.6 \\<br /> P(A) &amp; = 0.75 \\<br /> \text{Need} &amp; \\<br /> P(B) &amp; \\<br /> P(A \cap B) \text{ (instead of } &amp; P(A \mid B) \text{?)}<br /> \end{align*}<br />
 
statdad said:
If you are given P(A \mid B) why do you need to calculate it?

To be clear: are these the items you are given and the items you are to find?
<br /> \begin{align*}<br /> P(A \mid B) &amp; = 0.8 \\<br /> P(B \mid A&#039;) &amp; = 0.6 \\<br /> P(A) &amp; = 0.75 \\<br /> \text{Need} &amp; \\<br /> P(B) &amp; \\<br /> P(A \cap B) \text{ (instead of } &amp; P(A \mid B) \text{?)}<br /> \end{align*}<br />
sorry the terms given are P(B/A)= 0.8 , P(B/A")=0.6 and P(A)=0.75 I need to find P(A/B) and P(B)
 
Well, if you have P(B \mid A) and P(A) you can calculate P(A \cap B) . You can also find P(A&#039;) and
then get P(A&#039; \cap B). What will P(A \cap B) and P(A&#039; \cap B) together get you? Once you have that you can finish the questions.
 

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