Question

A box contains 20 tickets which are numbered from 1 to 20. If one card is drawn at random from the box, find the probability that the drawn card bears a perfect square number.

• A. $\frac{1}{20}$
• B. $\frac{1}{10}$
• C. $\frac{3}{20}$
• D. $\frac{1}{5}$

Answer 1

The correct option is D $\frac{1}{5}$

Total no. of outcomes(counting of tickets from 1 to 20) = 20
Favorable outcomes which are perfect square numbers = (1, 4, 9, 16)
For an event $\text{E, Probability P(E)}$ = $\frac{\text{Number of outcomes favorable to E}}{\text{Number of all possible outcomes of the experiment}}$

$\therefore$ Total no. of favourable outcomes
$=4$
P (perfect square numbered card )
$=\frac{4}{20}=\frac{1}{5}$