Question

Two aeroplanes $I$ and $II$ bomb a target in succession. The probability of $I$ and $II$ scoring a hit correctly are $0.3$ and $0.2$ respectively. The second plane will bomb only if the first misses the target. The probability that the target is hit by the second plane is

• A. $0.06$
• B. $0.14$
• C. $0.32$
• D. $0.7$

Answer 1

Answer: (C)

$0.32$

Probability that the target is hit by the $II$ plane means Target Hit and that because of plane $II$.

Target Hit = $1-0.7\times 0.8=1-0.56=0.44$

Hit by second plane = $0.2\times 0.7=0.14$

So target hit by second plane P = $\frac{0.14}{0.44}=0.318$