Question

A number is selected at random from $1$ to $50$. What is the probability that it is a prime number

Answer 1

The total number of outcomes are $50$.

Now, if a number is selected at random then the possible outcomes that it is a prime number are

$\{2,3,5,7,11,13,17,19,23,29,31,37,41,43,47\}$, which means the number of favourable outcome is $15$.

Therefore, probability $P$ of a prime number is:

$P=\frac{15}{50}=\frac{3}{10}$

Hence, the probability that it is a prime number is $\frac{3}{10}$.