Airplane Boarding Problem

, 2, \dots, n$. Passenger 1 has lost their ticket and picks a seat uniformly at random from all $n$ seats. Each subsequent passenger $k$ (for $k = 2, 3, \dots, n$) takes their assigned seat if it is available; otherwise, they pick uniformly at random from the remaining empty seats. 1. Compute the probability that passenger $n$ sits in their own seat (seat $n$). 2. Compute $E[\text{number of passengers who do NOT sit in their assigned seat}]$.