Question

You roll a number cube. What is the probability that you roll an even number or a number less than 5?

Answer 1

Let’s first see the probability of landing an even number. We have 6 sides, and 3 are labeled with an even number. So our chances of rolling a number cube are 3/6 (or 1/2 when simplified).

Next, the probability of rolling a number less then five is 4/6 (or 2/3 simplified), since we have 4 sides labeled with a number less than 5.

To compute two or more probabilities, we multiply them. In this case, the fractions already share the same denominator, 6 (because it’s a cube with 6 sides). So we get:

3/6 * 4/6

We then square 6, which is 36, and multiply 3 by 4, which is 12. This gives us 12/36, which is 1/3 in simplified form.

So there’s out answer: 1/3.