"mary paid $2 for a bottle of orange juice" can this be expressed as a rate?

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?

Which one ? is the answer and how to find this answer

Find the dimensions of the circle. area = 64π in.² r= in.