Question

Steve will roll a number cube, numbered 1-6, twice. What is the probability

of rolling a number > 3, then rolling a prime number? Simplify your answer!

Answer 1

25%

Explanation:

First we calculate the probability of rolling a number greater than 3, that is, it can be 4, 5 or 6.

The probability of each number is 1/6, so:

P1 = (1/6) + (1/6) + (1/6) = 3/6 = 1/2

Then, we calculate the probability of rolling a prime number, that is, 2, 3 or 5.

As we have again 3 numbers, the probability P2 will also be 1/2

Then, the final probability is the product of both P1 and P2:

P = P1 * P2 = (1/2) * (1/2) = 1/4 = 25%