Question

A bag contains 25 cards numbered from 1 to 25. A card is drawn at random from the bag. Find the probability that the number on the drawn card is
a) Divisible by 3 or 5.
b) Aperfectsquarenumber.

Answer 1

Cards contains number from 1 to 25

n(C)=25

a)Divisible by 3 or 5

let A be the number of cards divisible by 3 or 5 from 1 to 25

A=(3, 5, 6, 9, 10, 12, 15, 18, 20, 21, 24, 25)

n(A)=12

p=probability

p(A)=n(A)/ n(C)

= 12/25

b)A perfect square

let B be the set of perfect square from 1 to 25

B= ( 1, 4, 9, 16, 25)

n(B)= 5

p(B)= n(B) / n (A)

= 5/ 25

=1/5