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NDA Math Probability

Question : 61 of 100

Marks: +1, -0

Solution:

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

0.7^{n}=0.2

n\log0.7=\log0.2

\Rightarrow 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.

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