Question

Hundred identical cards are numbered from 1 to 100. The cards are well shuffled and then a card is drawn. Find the probability that the number on the card drawn is a multiple of 5.

Answer 1

There are 100 cards from which one card is drawn. 

Total number of elementary events = n(S) = 100 

From numbers 1 to 100, there are 20 numbers which are multiple of 5 i.e. {5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100}

Favorable number of events = n(E) = 20 

Probability of selecting a card with a multiple of 5

= `(n(E))/(n(S))`

= `20/100`

= `1/5`