Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn has a number which is a multiple of 3 or 5 ?

Answer: Option D

Here, S = {1, 2, 3, 4, ....., 19, 20}
Let E = event of getting a multiple of 3 or 5 = {3, 6, 9, 12, 15, 18, 5, 10, 20}
$$\therefore P(E)=\frac{n(E)}{n(S)}=\frac{9}{20}$$