Find the weight each backpack would contain if the total weight was redistributed equally among all the backpacks

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?

How do you use the elimination method for this question? explain, because i really want to understand!

Janet drove 300 miles in 4.5 hours. write an equation to find the rate at which she was traveling