To solve this problem, we need to identify the outcomes that match each event and then calculate the probability of each event. The probability of each outcome is equal since the number cube is fair.
- Event A: Two or more odd numbers - Identify outcomes with at least two 'O's.
- Event B: Exactly one odd number - Identify outcomes with exactly one 'O'.
- Event C: An even number on the first roll - Identify outcomes starting with 'E'.
The probability of each event is the number of favorable outcomes divided by the total number of outcomes (which is 8).
Event A requires two or more odd numbers. The outcomes that satisfy this condition are:
\[ \text{OOO, EOO, OEO, OOE} \]
The probability of Event A is the number of favorable outcomes divided by the total number of outcomes:
\[ P(A) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} = \frac{4}{8} = \frac{1}{2} \]
Event B requires exactly one odd number. The outcomes that satisfy this condition are:
\[ \text{OEE, EEO, EOE} \]
The probability of Event B is the number of favorable outcomes divided by the total number of outcomes:
\[ P(B) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} = \frac{3}{8} \]
Event C requires an even number on the first roll. The outcomes that satisfy this condition are:
\[ \text{EEE, EEO, EOO, EOE} \]
The probability of Event C is the number of favorable outcomes divided by the total number of outcomes:
\[ P(C) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} = \frac{4}{8} = \frac{1}{2} \]
- Event A outcomes: \(\text{OOO, EOO, OEO, OOE}\)
- Probability of Event A: \(\boxed{\frac{1}{2}}\)
- Event B outcomes: \(\text{OEE, EEO, EOE}\)
- Probability of Event B: \(\boxed{\frac{3}{8}}\)
- Event C outcomes: \(\text{EEE, EEO, EOO, EOE}\)
- Probability of Event C: \(\boxed{\frac{1}{2}}\)