Question

A card is drawn from a packet of $100$ cards numbered $1$ to $100$. What is the probability of drawing a number which is a square?

• A. $\frac{1}{10}$
• B. $\frac{9}{100}$
• C. $\frac{1}{100}$
• D. $\frac{2}{100}$

Answer 1

The correct option is A $\frac{1}{10}$

A card is drawn from a packet of $100$ cards numbered $1$ to $100$.

Total number of cards $=100$.

$\Rightarrow n\left(S\right)=100$

Let $A$ be the event of drawing a number which is a square.

$A=\{1,4,9,16,25,36,49,64,81,100\}$

$\Rightarrow n\left(A\right)=10$

Therefore, the probability of drawing a number which is a square is $P\left(A\right)=\frac{n\left(A\right)}{n\left(S\right)}$

$P\left(A\right)=\frac{10}{100}$ $=\frac{1}{10}$

Therefore, the probability of drawing a number which is a square is $\frac{1}{10}$.