Question

Cards, marked with numbers $5$ to $50$, are placed in a box and mixed thoroughly. A card is drawn from the box at random. Find the probability that the number on the card taken is a prime number less than $10$.

Answer 1

Total number of ways to select a card$=46$ (cards are marked $5$ to $50$)

Prime numbers less than $10=5$ and $7$

$\therefore$ Number of ways to select a card with a prime number less than $10=2$

$\therefore P\left(aprimenumberlessthan10\right)=\frac{2}{46}=\frac{1}{23}$