Question

A soldier fires three bullets on enemy. The probability that the enemy will be killed by one bullet is 0.7. What is the probability that the enemy is still alive?

Answer 1

The answer will be 0.3 that is 1-0.7

Answer 2

The probability that the enemy is still alive after firing 3 bullets is 0.027.

Probability that after one bullet is fired, enemy is killed = 0.7

∴ Probability that the enemy is still alive after one bullet is fired = 1 - 0.7 = 0.3

∴ Probability that the enemy is still alive after three bullet is fired = 0.3 × 0.3 ×  0.3 = 0.027

Required probability is 0.027