Question

In a box containing 100 bulbs, 10 are defective. The probability that out of a sample of 5 bulbs, none is defective is

(A) 10⁻¹

(B) `(1/2)^5`

(C) `(9/10)^5`

(D) 9/10

Answer 1

The repeated selections of defective bulbs from a box are Bernoulli trials. Let X denote the number of defective bulbs out of a sample of 5 bulbs.

Probability of getting a defective bulb, p = 10/100 = 1/10

The correct answer is C.