Question

20 tickets, on which numbers 1 to 20 are written, are mixed thoroughly and then a ticket is drawn at random out of them. Find the probability that the number on the drawn ticket is a multiple of 3 or 7 ?

Answer 1

Total number of outcomes = 20
Possible outcomes = 3, 6, 7, 9, 12, 14, 15 and 18
∴ Number of favourable outcomes = 8

Probability =\[\frac{\text{Number of favourable outcomes}}{\text{Total number of outcomes}}\]

\[\therefore \text{Probability that the number on the drawn ticket is a multiple of 3 or 7 =} \frac{8}{20} = \frac{2}{5}\]