Describe a real-life situation that can be modeled by a function (a relation in which every input value corresponds to only one output value). Identify the input value and the output value of the function, and provide justification that your relation does, in fact, represent a function. Create a function in the form y = f(x) that models the relation described. You may choose variables in place of y or x that better represent the relation, as seen in the provided example.
Identify the domain and range of your function, using proper mathematical notation.