An anti aircraft gun take four shots at an enemy plane moving away from it. The probability of hitting the plane at the first, second, third and fourth shot are 0.4, 0.3, 0.2 and 0.1 respectively. The probability that the gun hit the plane is :- (A) 0.25 (B) 0.21 (C) 0.16 (D) 0.6976

Explanation

The probability that the gun hits the plane at 1 st shot `=0.4=p 1`

2nd shot, `{p} 2=0.3,3` rd shot, `{p} 3=0.2` and 4 th shot, `{p} 4=0.1`

Let `q 1, q 2, q 3, q 4` be the probability that the gun does not hit the plane at 1 st, 2 nd, 3 rd, and 4 th shot respectively.


q_{1}=1-0.4=0.6

q 2=1-0.3=0.7

q 3=1-0.2=0.8

q 4=1-0.1=0.9

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