Easy MCQ +4 / -1 PYQ · JEE Mains 2021

When a missile is fired from a ship, the probability that it is intercepted is ${1 \over 3}$ and the probability that the missile hits the target, given that it is not intercepted, is ${3 \over 4}$. If three missiles are fired independently from the ship, then the probability that all three hit the target, is :

  1. A ${3 \over 4}$
  2. B ${3 \over 8}$
  3. C ${1 \over 27}$
  4. D ${1 \over 8}$ Correct answer

Solution

Probability of not getting intercepted = ${2 \over 3}$<br><br>When it is not intercepted, probability of missile hitting target = ${3 \over 4}$<br><br>$\therefore$ So when such 3 missiles launched then P (all 3 hitting the target) <br><br>= ${\left( {{2 \over 3} \times {3 \over 4}} \right)}$ $\times$ ${\left( {{2 \over 3} \times {3 \over 4}} \right)}$ $\times$ ${\left( {{2 \over 3} \times {3 \over 4}} \right)}$ <br><br>$= {1 \over 8}$

About this question

Subject: Mathematics · Chapter: Probability · Topic: Classical and Axiomatic Probability

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