# Math Help - bulb probability

1. ## bulb probability

Two percent of the bulbs produced by a factory are not usable .Find the smallest number of bulbs that must be examined so that the probabiltiy of obtaining at least one non-usable bulb exceeds 0.5 .

2. Originally Posted by thereddevils
Two percent of the bulbs produced by a factory are not usable .Find the smallest number of bulbs that must be examined so that the probabiltiy of obtaining at least one non-usable bulb exceeds 0.5 .
X ~ Binomial(n = ?, p = 0.02).

Solve $\Pr(X \geq 1) > 0.5 \Rightarrow \Pr(X = 0) < 0.5$ for the smallest integer value of n.