Question

A bag contains 20 tickets numbered 1 to 20. Two tickets are drawn at random. The probability that both the numbers on the ticket are prime is ______.

Options

• `4/95`

• `14/95`

• `17/95`

• `9/95`

Answer 1

A bag contains 20 tickets numbered 1 to 20. Two tickets are drawn at random. The probability that both the numbers on the ticket are prime is `underlinebb(14/95)`.

Explanation:

Total cases = ²⁰C₂ = `20.19/2` = 190

Prime numbers = 2, 3, 5, 7, 11, 13, 17, 19 = 8

Favourable cases = ⁸C₂ = 28

Required probability = `28/190` = `14/95`