Question

Thirty identical cards are marked with numbers 1 to 30. If one card is drawn at random, find the probability that it is a multiple of 3 or 5.

Answer 1

There are 30 cards from which one card is drawn. 

Total number of elementary events = n(S) = 30 

From numbers 1 to 30, there are 14 numbers which are multiple of 3 or 5 i.e. {3, 5, 6, 9, 10, 12, 15, 18, 20, 21, 24, 25, 27, 30} 

Favorable number of events = n(E) = 14 

Probability of selecting a card with a multiple of 3 or 5 = `(n(E))/(n(S)) = 14/30 = 7/15`