A random sample of 12 flights was taken at an airport where normally 75% of flights arrive on time. The mean number of on-time flights would be 0.75 * 12 = 9, and the variance would be 0.75 * 0.25 * 12 = 3. Using Chebyshev's Inequality, the maximum probability of 7 or fewer flights or 11 or more flights being on time is 1/9. The exact probability can be calculated using the binomial probability formula.