Question

A number is chosen from $1$ to $20$. Find the probability that the number chosen is a prime number.

Answer 1

Total number of cases = 20

Prime number 1 to 20

$2,3,5,7,11,13,17,19$

Favourable cases =8

probabilities of choosen prime numbers

$\frac{8}{20}=\frac{2}{5}$