Question:
Tickets numbered 1 to 20 are mixed up and then a ticket is drawn at random. What is the probability that the ticket drawn bears a number which is a multiple of 3?
Solution:
GIVEN: Tickets are marked from 1 to 20 are mixed up. One ticket is picked at random.
TO FIND: Probability that the ticket bears a multiple of 3
Total number of cards is 20
Cards marked multiple of 3 number are 3,6,9,12,15,18
Total number of cards marked multiple of 3 are 6
We know that PROBABILITY = 
Hence probability of getting a multiple of 3 on the ticket =
Hence probability of getting a multiple of 3 on the ticket 