54 equals 9 more than a number t

Ineed to learn how to solve this problem

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

The step function g(x) is defined as shown.what is the range of g(x)? ***answer choices in picture.