Answer:
4 M + 2 N = 120
Step-by-step explanation:
If we name "M" the number of tables for four people, and "N" the number of tables for two people, then the total number of people to be seated using M tables (of four people) would be the product "4 * M".
Similarly, the total number of people to be seated if the owner has N number of two person tables, would be: "2 * N".
Therefore, if the owner has M four people tables and N two person tables, the total number of people seated at the restaurant would be the addition:
4 * M + 2 * N. Since he wants this number to be 120, we complete the equation making this expression equal to 120:
4 * M + 2 * N = 120