A standard six-sided number cube (die) has the numbers 1, 2, 3, 4, 5, and 6. Out of these, the even numbers are 2, 4, and 6.
So, there are 3 even numbers out of a total of 6 numbers. The probability \( P \) of rolling an even number is:
\[ P(\text{even}) = \frac{\text{number of even outcomes}}{\text{total number of outcomes}} = \frac{3}{6} = \frac{1}{2} \]
If you roll the die 30 times, the expected number of times you would roll an even number can be calculated by multiplying the probability of rolling an even number by the number of rolls:
\[ \text{Expected number of even rolls} = P(\text{even}) \times \text{number of rolls} = \frac{1}{2} \times 30 = 15 \]
Therefore, you can expect to roll an even number approximately 15 times when rolling the die 30 times.