Question

The box contains 20 balls bearing number 1,2,3,4,......20 a ball is drawn at random from the box . What is the probability that the number on the balls is 1. An odd number 2. Divisible by 2 or 3 .3.Prime numbers 4. Not divisible by 10.

Answer 1

n(s)=20
event A :
A=( 1 ,3,5,7,9,11,13,15,17,19) n(A)=10
event B:
B =(6,12,18) n(B)=3
p(A)=10/20=1/2
P(B)=3/20