We are given a number cube (a six-sided die) that is rolled three times. Each roll can result in an odd or even number. The outcomes are represented by strings such as OEE, where 'O' stands for an odd number and 'E' stands for an even number. We need to determine which outcomes belong to each event and calculate the probability of each event.
Event A: An odd number on each of the last two rolls.
We need to find outcomes where the second and third rolls are odd. The possible outcomes are:
These are the only outcomes where the last two rolls are odd.
There are 8 possible outcomes in total, and 2 of them satisfy Event A. Since each outcome is equally likely, the probability of Event A is:
\[
P(A) = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}} = \frac{2}{8} = 0.25
\]
Event B: Two or more odd numbers.
We need to find outcomes with at least two odd numbers. The possible outcomes are:
These outcomes have two or more odd numbers.
There are 5 outcomes that satisfy Event B. Thus, the probability of Event B is:
\[
P(B) = \frac{5}{8} = 0.625
\]
Event C: Exactly one odd number.
We need to find outcomes with exactly one odd number. The possible outcomes are:
These outcomes have exactly one odd number.
There are 2 outcomes that satisfy Event C. Thus, the probability of Event C is:
\[
P(C) = \frac{2}{8} = 0.25
\]
- Event A: Outcomes are OOE, OOO. Probability is \(\boxed{0.25}\).
- Event B: Outcomes are OOE, OEO, EOO, OEE, OOO. Probability is \(\boxed{0.625}\).
- Event C: Outcomes are EOO, EEE. Probability is \(\boxed{0.25}\).