Question

The probability that atleast one of the events $A,B$ happens is $0.6$. If probability of their simultaneously happening is $0.5$, then $P\left(\overline{A}\right)+P\left(\overline{B}\right)=$

• A. $0.4$
• B. $0.8$
• C. $0.9$
• D. $1.4$

Answer 1

Answer: (C)

$0.9$

$P(A\cup B)=0.6P(A\cap B)=0.5$

$P\left(\overline{A}\right)+P\left(\overline{B}\right)=1-P\left(A\right)+1-P\left(B\right)$

$=2-\left\{P\right(A\cup B)+P(A\cap B\left)\right\}=0.9$