Describing Domain and Range

The minimum number of traveled miles is $0.$ To determine the cost that corresponds with this distance, we can substitute $x=0$ into the equation and solve for $y.$ The minimum cost of a taxi ride is $\$2.50.$ It is given that there is enough money to travel most $30$ miles. We can consider this the maximum distance. To determine the cost of such a ride, we will substitute $x=30$ into the equation and solve for $y.$ Since $y=122.5$ when $x=30,$ the maximum cost of a ride is $\$122.50.$ From our work above, we have established that Kareem can travel from $0$ to $30$ miles and the cost is from $\$2.50$ to $\$122.50.$ These values represent the lower and upper boundaries of our domain and range. $\begin{aligned} D\text{: }& 0\leq x \leq 30\\ R\text{: }& 2.5\leq y \leq 122.5 \end{aligned}$