16. (10 points) A bus has 78 seats, and it starts its journey empty. At the first stop, one passenger boards, at the second stop, two passengers board, at the third stop, three passengers board, and so on. After how many stops will the bus be full of passengers?
【Solution】Solution: Let the bus be full of passengers after the $n$-th station, we get:
$$
\begin{array}{l}
{[1+1+(n-1) \times 1] \times n \div 2=78} \\
{[2+n-1] \times n \div 2=78,} \\
{[1+n] \times n \div 2=78,} \\
\quad(1+n) \times n=156,
\end{array}
$$

Since $12 \times 13=156$,
i.e., $n=12$.
Answer: After 12 stations, the bus is full of passengers.