Question

A box contains 19 balls bearing numbers 1, 2, 3, ..., 19 respectively. A ball is drawn at random from the box. Find the probability that the number on the ball is (3 Marks) (i) a prime number (ii) an even number (iii)a number divisible by 3.

Answer 1

Answer:

i) 9/19

ii) 9/19

iii) 6/19

Answer 2

Answer:

n(s) =19

I) the number of a ball is prime number (a) =

1,2,3,5,7,11,13,17,19

n(a) =9

p(a) =n(a) /n(s) =9/19

ii) an even number (b) =2, 4,6,8,10,12,14,16,18

n(b) =9

p(b) =n(b) /n(s) =9/19

iii) number divisible by 3(c) =3, 6,9,12,15,18

n(c) =6

p(c) =n(c) /n(s) =6/19