Question

Cards marked with number $2$ to $101$ are placed in a box and mixed thoroughly. One card is drawn from this box. Find the probability that the number of the card is a prime number less than $20$.

Answer 1

We have,

Cards marked with number 2 to 101 are placed in a box.

Total number of cards $=100$

Even cards$=50$

Odd cards$=50$

Prime number les than $20$:$2,3,5,7,11,13,17,19$

Number of cards prime number $=8$

Then,

According to given question,

Probability of cards prime number $=\frac{8}{100}=\frac{2}{25}$

Hence, this is the answer.