Question

What is the probability of the event that a number chosen from 1 to 100 is a prime number?

(A) 1/5

(B) 6/25

(C) 1/4

(D) 13/50

Answer 1

Correct answer is

(C) 1/4

n(S) = 100

Let A be the event that the number chosen is a prime number.

∴ A = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97}

∴ n(A) = 25

∴ P(A) = \(\frac{n(A)}{n(S)} = \frac{25}{100} = \frac{1}{4}\)