Question

There are 600 electric bulbs in a box, out of which 20 bulbs are defective. If one bulb is chosen at random from the box, what is the probability that it is defective?
(a) $\frac{1}{19}$

(b) $\frac{1}{20}$

(c) $\frac{1}{30}$

(d) $\frac{29}{30}$

Answer 1

(c) $\frac{1}{30}$

Explanation:
Total number of bulbs in the box = 600
Number of defective bulbs = 20

Let E be the event that the chosen bulb is defective.

∴ Required probability = P(E) = $\frac{20}{600}=\frac{1}{30}$