Question

A box contains 20 balls bearing numbers 1 , 2 3, 4, 5, ......20, A ball is drawn at random from the box. What is the probability that number on the ball is composite number ?

• A. $\frac{11}{20}$
• B. $\frac{8}{20}$
• C. $\frac{9}{20}$
• D. $\frac{7}{20}$

Answer 1

The correct option is A $\frac{11}{20}$

Possible outcomes = 20
Favourable outcomes are 4,6,8,9,10,12,14,15,16,18,20=11
$\therefore$ Required probability $=\frac{11}{20}.$