If 4/5 of a population of a certain town is considered to be middle class and the population of the town is 2000 how many people are considered middle class

Ineed big ! the cost of a school banquet is $25 plus $15 for each person attending. create a table, sketch the graph, and write an equation in slope-intercept and point-slope form that gives total cost as a function of the number of people attending. what is the cost for 77 people?