Question

A die is thrown. Find the probability of getting 

(i) a prime number, 

(ii) a number greater than or equal to 3.

Answer 1

Let S be the sample when a die is thrown.

Then S = {1, 2, 3, 4, 5, 6}, n(S) = 6 

Let A be the event of getting a prime number. 

A = {2, 3, 5}, n(A) = 3 

Let B be the event of getting a number greater than or equal to 3. 

B = {3, 4, 5, 6}, n(B) = 4

(i) P(a prime number) = \(\frac{n(A)}{n(S)}=\frac{3}{6}=\frac{1}{2}\)

(ii) P(a number ≥ 3) = \(\frac{n(B)}{n(S)}=\frac{4}{6}=\frac{2}{3}\)