Question

$A$ and $B$ are two events such that $P\left(A\right)=0.2$ and $P\left(AB\right)=0.7$. If $A$ and $B$ are independent events then $P\left(B\right)$ equals:

• A. $\frac{2}{7}$
• B. $\frac{7}{9}$
• C. $\frac{7}{2}$
• D. none of these

Answer 1

The correct option is C $\frac{7}{2}$

Given : $P\left(A\right)=0.2$ and $P\left(AB\right)=0.7,A$ and $B$ are independent.

To Find : $P\left(AB\right)$

Solution : We know that if $A$ and $B$ are independent, then $P\left(AB\right)=P\left(A\right)P\left(B\right)$

So, $0.7=0.2$ $\times P\left(B\right)$

$P\left(B\right)=0.7/0.2$

$P\left(B\right)=7/2$