Statistics And Probability Question 225

Question: A bag contains tickets numbered from 1 to 20. Two tickets are drawn. The probability that both the numbers are prime, is

[AISSE 1981]

Options:

A) $ \frac{14}{95} $

B) $ \frac{7}{95} $

C) $ \frac{1}{95} $

D) None of these

Show Answer

Answer:

Correct Answer: A

Solution:

  •                 There are 8 prime numbers  $ 2,3,5,7,11,13,17,19. $                     Hence required probability  $ =\frac{{}^{8}C_2}{{}^{20}C_2}=\frac{8.7}{20\,.\,19}=\frac{14}{95} $ .