Question

If a number is selected at random from first 100 natural number, then the probability that it is a prime

• A. 1/3
• B. ¼
• C. ½
• D. 2/3

Answer 1

Answer: (B)

¼

Answer 2

n(s) = 100.

Let E be the event of selecting a prime.

E= {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(5) = 25

P(5) = $\frac { 25 } { 100 } = \frac { 1 } { 4 }$.