Please explain the correct answer in detail with the mathematical steps necessary to find the answer! Thank you.

(Table: Three-Country Oil Production) Refer to the table. Suppose that three countries are engaged in oil production. For simplicity, assume zero costs so that revenue equals prot. If the countries create a cartel and agree to mimic monopoly-like behavior, what level of output would each rm produce? Ton-mm: - mm_ ___E 70 50 4-0 30 200 700 9 400 1,200