Question

A die is thrown. Find the probability of getting

1. a prime number
2. 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) = `("n"("A"))/("n"("S")) = 3/6 = 1/2`

ii. P(a number ≥ 3) = `("n"("B"))/("n"("S")) = 4/6 = 2/3`