Probability Question 385
Two events A and B are such that P(not B) = 0.8, $ P(A\cup B)=0.5 $ and $ P(A|B)=0.4. $ Then P(A) is equal to
Options:
A) 0.28
B) 0.32
C) 0.38
D) None of the above
Show Answer
Answer:
Correct Answer: C
Solution:
$ \because P(\bar{B})=0.8\Rightarrow P(B)=0.2 $
$ P(A\cup B)=0.5\land P(A|B)=0.4 $
$ \because P(A\cap B)=P(B)\times P(A|B)=0.2\times 0.4=0.08 $
$ P(A)=P(A\cup B)-P(B)+P(A\cap B) $
$ P(A)=0.5-0.2+0.08=0.38 $
BETA
