- The random variable "number of students" is discrete. The possible values are \(0, 1, 2, \ldots\).
- The random variable "amount of snow" is continuous. The possible values are \(x \geq 0\).
- The random variable "flight time" is continuous. The possible values are \(x \geq 0\).
Thus, the answers are:
- (a) Discrete, possible values: \(0, 1, 2, \ldots\)
- (b) Continuous, possible values: \(x \geq 0\)
- (c) Continuous, possible values: \(x \geq 0\)
\[
\boxed{
\begin{align_}
\text{(a)} & \text{ Discrete} \\
\text{(b)} & \text{ Continuous} \\
\text{(c)} & \text{ Continuous}
\end{align_}
}
\]