we know that
The Domain is the the set of all the input values
The Range is the set of all output values
In this problem
the input values or x-coordinates is the time
and
the output value or y-coordinate is the cost
The Domain is equal to the interval (0, 12}
All real numbers greater than zero and less than or equal to 12
The range is equal to the set (10,15,20,25)
The minimum value is $10 and the maximum value is $25