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

In summary, given P(B/A)=0.8, P(B/A")=0.6 and P(A)=0.75, we can calculate P(A/B) by using the equation P(A/B)= P(B/A)P(A), which gives us P(A/B)= 0.8*0.75=0.6. We can also find P(B) by using the equations P(B/A)= P(A/B)P(B) and P(B/A")= P(A'/B)P(B), which gives us P(B)=0.6/0.8=0.75 and P(B)=0.6/0.6=1, respectively. Thus, we can calculate P(A/B)=0
  • #1
chwala
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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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  • #2
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)## ?
 
  • #3
If you are given [itex] P(A \mid B) [/itex] why do you need to calculate it?

To be clear: are these the items you are given and the items you are to find?
[tex]
\begin{align*}
P(A \mid B) & = 0.8 \\
P(B \mid A') & = 0.6 \\
P(A) & = 0.75 \\
\text{Need} & \\
P(B) & \\
P(A \cap B) \text{ (instead of } & P(A \mid B) \text{?)}
\end{align*}
[/tex]
 
  • #4
statdad said:
If you are given [itex] P(A \mid B) [/itex] why do you need to calculate it?

To be clear: are these the items you are given and the items you are to find?
[tex]
\begin{align*}
P(A \mid B) & = 0.8 \\
P(B \mid A') & = 0.6 \\
P(A) & = 0.75 \\
\text{Need} & \\
P(B) & \\
P(A \cap B) \text{ (instead of } & P(A \mid B) \text{?)}
\end{align*}
[/tex]
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)
 
  • #5
Well, if you have [itex] P(B \mid A) [/itex] and [itex] P(A) [/itex] you can calculate [itex] P(A \cap B) [/itex] . You can also find [itex] P(A') [/itex] and
then get [itex] P(A' \cap B) [/itex]. What will [itex] P(A \cap B) [/itex] and [itex] P(A' \cap B) [/itex] together get you? Once you have that you can finish the questions.
 

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

1. What is the formula for finding probability?

The formula for finding probability is: P(A) = Number of favorable outcomes / Total number of possible outcomes.

2. What is P(B) in probability?

P(B) is the probability of event B occurring, independent of any other events.

3. How do you find P(A/B)?

To find P(A/B), you use the formula: P(A/B) = P(A ∩ B) / P(B), where P(A ∩ B) represents the probability of both events A and B occurring together.

4. Can P(A/B) be greater than 1?

No, P(A/B) cannot be greater than 1. The maximum value for probability is 1, which represents a 100% chance of an event occurring.

5. What is the difference between P(A/B) and P(B/A)?

P(A/B) represents the probability of event A occurring given that event B has already occurred. P(B/A), on the other hand, represents the probability of event B occurring given that event A has already occurred. These probabilities can be different if events A and B are not independent.

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