1. **State the problem:** We have an urn with 10 red balls and 8 white balls. One ball is drawn at random. We need to find the probability that the ball drawn is white. 2. **Formula for probability:** The probability of an event is given by $$\text{Probability} = \frac{\text{Number of favorable outcomes}}{\text{Total number of outcomes}}$$ 3. **Identify favorable and total outcomes:** - Number of favorable outcomes (white balls) = 8 - Total number of balls = 10 (red) + 8 (white) = 18 4. **Calculate the probability:** $$P(\text{white ball}) = \frac{8}{18}$$ 5. **Simplify the fraction:** $$\frac{8}{18} = \frac{4}{9}$$ 6. **Final answer:** The probability that a white ball is drawn is $$\boxed{\frac{4}{9}}$$