A certain type of missile hits the 36 probability target with p 0.3. What is the least number of missiles should be fired so that there is at least an 80% probability that the target is hit?

Options

A. 5
B. 6
C. 7
D. None of the above

Answer

A

Explanation

Probaility of hitting the target = 0.3
If n is the no of times that the Missile is fired .
`therefore` Probability of hitting at least one ` = 1- [1-0.3]^(n) = 0.8`
` 0.7^(n) = 0.2`
n log 0.7 = log 0.2
for n = 4 , `p lt 0.8`
`taken n = 5 .
n = 5
Hence 5 missiles should be fired so that there is at lest 80% prob. that the target is hit.