Question

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

• A. $\frac{1}{2}$
• B. $\frac{1}{4}$
• C. $\frac{1}{5}$
• D. $\frac{1}{6}$

Answer 1

The correct option is A $\frac{1}{2}$

Here, total number of balls is $20$.
$\therefore$ Total number of elementary events $=20$
The number selected will be odd number, if it is elected from $\{1,3,5,7,9,11,13,15,17,19\}$
$\therefore$ Favourable number of.elementary events $=10$
Hence, $P($An odd number$)=$ $\frac{10}{20}=\frac{1}{2}$