SOLUTION: How do I find P(B∩A’)? For example, I have P(B) = 0.60. I know the following information: P(A|B)=0.30. P(B|A)=0.60. P(A∩B)=0.18. So would P(B∩A’) be 0.60 + 1-P(A)

Algebra.Com
Question 1117717: How do I find P(B∩A’)? For example, I have P(B) = 0.60. I know the following information: P(A|B)=0.30. P(B|A)=0.60. P(A∩B)=0.18. So would P(B∩A’) be 0.60 + 1-P(A)? Also, what would A be?

Answer by greenestamps(13203)   (Show Source): You can put this solution on YOUR website!


As I read your question, the actual given information is

P(A|B)=0.30; P(B|A)=0.60; P(A and B)=0.18.

I personally find it easiest to see what is going on in this kind of problem using a Venn diagram.

Whether with a Venn diagram or with symbols, P(A|B)=0.30 means that P(A and B) is only 0.30 times P(B):

0.18 = 0.30*P(B) --> P(B) = 0.18/0.30 = 0.60

Then since P(B) is 0.60 and P(A and B) is 0.18, P(B and A') is 0.60-0.18 = 0.42.

Similarly, P(A and B)=0.18 and P(B|A)=0.60 means

0.18 = 0.60*P(A) --> P(A) = 0.18/0.60 = 0.30

and that makes P(A and B') = 0.30-0.18 = 0.12.

------------------------------------------------------

The preceding is a formal way of solving your problem.

Now here is the actual method I used for getting the answer of P(B and A')=0.42.

(Look at a Venn diagram to follow the logic of this method.)

Since P(A|B)=0.30, P(A'|B)=0.70.

Then the ratio of P(B and A') to P(B and A) is 0.70:0.30.

And so P(B and A') is

RELATED QUESTIONS

ii. If P(B)=0.30, P(A│B)=0.60, P(B’)=0.70 and P(A│B’)=0.50, find... (answered by ikleyn)
Use Table A0 in Appendix I to find the following: a) P(x < 12) for n = 20, p = 0.5 b) (answered by math_tutor2020)
4. Compute the probability. a. If P(A) = 0.2 , P(B)= 0.4, and P(A and B) = 0.1, find... (answered by ikleyn)
How do I know the differences between P(A OR B) and P(A and... (answered by swincher4391)
If P(A) = 1/2,P(B) = 7/10,P(AUB) = 1,find (i) P (A ∩ B) (ii) P(A' U B') (answered by Bay0913,0123467)
Use the given information to find the indicated probability. P(A ∩ B) = .1, P(B) =... (answered by edjones)
If I know P(A^B), how do I get P(A^Bcomplement)...where ^ means intersection ....for... (answered by stanbon)
Find the missing probability. P(A) = 0.5 P(B) = 0.6 P(A and B) = ? P(A) = 0.31... (answered by ikleyn)
P(A) = 0.31 P(B given A) = 0.8 P(A and B) =... (answered by ikleyn)