Someone kill me more math

What 2 forces allow things to fall ‍♀️‍♀️

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?

You deposit $5000 each year into an account earning 3% interest compounded annually. how much will you have in the account in 30 years?