Question

From 25 identical cards, numbered 1, 2, 3, 4, 5, ......, 24, 25; one card is drawn at random. Find the probability that the number on the card drawn is a multiple of 3.

Answer 1

There are 25 cards from which one card is drawn. 

Total number of elementary events = n(S) = 25 

From number 1 to 25, there are 8 number which are multiple of 3 i.e. {3, 6, 9, 12, 15, 18, 21, 24}

Favorable number of events = n(E) = 8 

Probability of selecting a card with a multiple of 3 = `(n(E))/(n(S)) = 8/25`