Problem
Paige has some cards. Each card has a colour on it. If she chooses a card at random, then \[ P(\text { blue })=\frac{5}{9} \text { and } P(\text { white })=\frac{1}{18} \text {. } \] Calculate $P$ (neither blue nor white). Give your answer as a fraction in its simplest form.
Solution
Step 1 ：Since the total probability of all possible outcomes is 1, we can subtract the probabilities of choosing a blue card and a white card from 1 to find the probability of choosing a card that is neither blue nor white: \(1 - \frac{5}{9} - \frac{1}{18}\)
Step 2 ：Simplify the expression: \(\boxed{\frac{7}{18}}\)
