Cards bearing numbers 2, 3, 4, ..., 11 are kept in a bag. A card is drawn at random from the bag.

Question:

Cards bearing numbers 2, 3, 4, ..., 11 are kept in a bag. A card is drawn at random from the bag. The probability of getting a card with a prime number is    

(a) $\frac{1}{2}$

(b) $\frac{2}{5}$

(C) $\frac{3}{10}$

 

(d) $\frac{5}{9}$

 

Solution:

​Total number of cards = 10.

Out of the given numbers, prime numbers are 2, 3, 5, 7 and 11.

Numbers of favourable outcomes = 5.

$\therefore \mathrm{P}$ (getting a prime number) $=\frac{\text { Number of favourable outcomes }}{\text { Number of all possible outcomes }}$

$=\frac{5}{10}=\frac{1}{2}$

Thus, the probability of getting a card with a prime number is $\frac{1}{2}$.

Hence, the correct answer is option (a).

 

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