The probability \( P(E) \) of an event \( E \) occurring is given by the ratio of the number of favorable outcomes \( n(E) \) to the total number of possible outcomes \( n(S) \).
Given:
- \( n(S) = 10 \) (total number of possible outcomes)
- \( n(E) = 5 \) (number of favorable outcomes)
The formula for probability is:
\[ P(E) = \frac{n(E)}{n(S)} \]
Substituting the given values:
\[ P(E) = \frac{5}{10} = \frac{1}{2} = 0.5 \]
So, the probability \( P(E) \) is \( 0.5 \).
