Ask a New Question
Menu

If you roll a standard number cube, determine the probability that you roll an even number or a 5.

a. 1/12
b. 2/3
c. 1/2
d. 1/6

1 answer

A standard number cube (or die) has six faces, numbered from 1 to 6. The even numbers on a die are 2, 4, and 6, and there's also the number 5.

We need to find the probability of rolling an even number or a 5.

  1. The even numbers on the die are:

    • 2
    • 4
    • 6
      This gives us a total of 3 outcomes.

  2. There’s also the number 5, which is a single outcome that we have not counted yet.

Now, we combine these outcomes:

  • Even numbers: 2, 4, 6 (3 outcomes)
  • The number 5 (1 outcome)

However, there is no overlap (we can't roll an even number and a 5 at the same time).

So, the total number of favorable outcomes is: \[ 3 \text{ (even numbers)} + 1 \text{ (the number 5)} = 4 \text{ favorable outcomes} \]

The total number of possible outcomes when rolling a dice is 6.

Therefore, the probability \( P \) of rolling an even number or a 5 is: \[ P = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} = \frac{4}{6} = \frac{2}{3} \]

Thus, the answer is b. 2/3.