11 In a free-throw test, as long as a person makes 3 shots, they are qualified and do not need to shoot anymore. However, each person can shoot at most 5 times. For a player with a shooting accuracy of $\frac{2}{3}$, the probability of passing the test is
(11) The probability that the player makes 3 out of 3 shots is $\left(\frac{2}{3}\right)^{3}=\frac{8}{27} ;$ the probability of making 3 out of 4 shots is $\frac{2}{3} \times\left(\frac{2}{3}\right)^{2} \times\left(\frac{1}{3}\right) \cdot \mathrm{C}_{3}^{2}=\frac{8}{27}$; the probability of making 3 out of 5 shots is $\frac{2}{3} \times\left(\frac{2}{3}\right)^{2} \times$ $\left(\frac{1}{3}\right)^{2} \cdot \mathrm{C}_{4}^{2}=\frac{16}{81}$. Therefore, the probability of passing the test is $\frac{8}{27}+\frac{8}{27}+\frac{16}{81}=\frac{64}{81}$.