Probability of hitting the forget =0.3 If’n' is the no. of times that the Missile is fired ∴ Probability of hitting at least once=1−[1−0.3]n=0.8 0.7n=0.2 nlog0.7=log0.2 ⇒n=4.512 for n=4;=p<0.8 take n=5 n=5 Hence 5 missiles should be fired so that there is at least 80% prob. that the target is hit.