To find the probability of rolling an even number or a 5 on a standard number cube, we first identify the possible outcomes.
A standard number cube has six faces numbered from 1 to 6. The even numbers on the cube are 2, 4, and 6.
The outcomes are:
- Even numbers: 2, 4, 6 (3 outcomes)
- Number 5: (1 outcome)
Next, we find the total outcomes in the event of rolling an even number or a 5. The outcomes we have are:
- 2
- 4
- 6
- 5
These outcomes are distinct. Thus, the total number of favorable outcomes is 4 (2, 4, 5, and 6).
The total number of possible outcomes when rolling a standard number cube is 6 (since the cube has six sides).
We calculate the probability as follows:
\[ P(\text{even number or 5}) = \frac{\text{Number of favorable outcomes}}{\text{Total number of possible outcomes}} = \frac{4}{6} = \frac{2}{3} \]
Thus, the probability that you roll an even number or a 5 is \(\frac{2}{3}\).
The answer is D. \(\frac{2}{3}\).