PLEASE HELP!!
A dining hall has 20 tables in it. Tables sit 6 and some only 4 people. When all the tables are filled a total of 104 people can be seated. Let s be the number of six-person tables and let f be the number of four-person tables. Write a system of equations that represents the information given above. Two equations with two variables in each one. You do not need to solve the system.