The probability of a man hitting a target is ${1 \over {10}}$. The least number of shots required, so that the probability of his hitting the target at least once is greater than ${1 \over {4}}$, is ____________.
Answer (integer)
3
Solution
We have, $1 -$(probability of all shots results in failure out of n trials) > ${1 \over 4}$<br><br>$\Rightarrow 1 - {\left( {{9 \over {10}}} \right)^n} > {1 \over 4}$<br><br>$$ \Rightarrow {3 \over 4} > {\left( {{9 \over {10}}} \right)^n} \Rightarrow n \ge 3$$
About this question
Subject: Mathematics · Chapter: Probability · Topic: Classical and Axiomatic Probability
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