Question

A die is thrown once. What is the probability of getting a prime number?
(a) $\frac{1}{3}$
(b) $\frac{1}{2}$
(c) $\frac{2}{3}$
(d) none of these

Answer 1

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

Explanation:
In a single throw of a die, the possible outcomes are:
1, 2, 3, 4, 5, 6
Total number of possible outcomes = 6
Let E be the event of getting a prime number.
Then, the favourable outcomes are 2, 3 and 5.
Number of favourable outcomes = 3
∴ Probability of getting a prime number = P (E) = $\frac{\mathrm{Number}\mathrm{of}\mathrm{favorable}\mathrm{outcomes}}{\mathrm{Total}\mathrm{number}\mathrm{of}\mathrm{possible}\mathrm{outcomes}}=\frac{3}{6}=\frac{1}{2}$