Do you think anyone could help me with these 2 questions?

1foot = 12 inches; 1 yard = 3 feet

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?

Find the difference (8ab+a+2) - (3ab+6)