2. The setting appears to be binomial. Therefore, sum the binomial probability theorem $\frac{n!}{k!(n - k)!}p^k(1 - p)^{n - k}$ (where n is the number of trials, k is the number of successes, and p is the probability of success) for k = 3, k = 4, ..., k = 9, and k = 10, or $\sum_{k=3}^{10} \frac{n!}{k!(n - k)!}p^k(1 - p)^{n - k}$.