Two firms, A and B, each currently emit 100 tons of chemicals into the air. The government has decided to reduce the pollution and from now on require a pollution permit for each ton of pollution emitted into the air. The government gives each firm 50 pollution permits, which it can either use of sell to the other firm. It costs Firm A $200 for each ton of pollution that it eliminates before it is emitted into the air, and it cots Firm B $100 for each ton of pollution that it eliminates before it is emitted into the air. After trading the permit, how many tons of pollution will Firm A emit