Numerical Example: Negative Externalities Assume the steel firm faces the following mb and mpc curves MB=300-Q MPC=20+Q Assume the fishery faces the following MD curve MD=40+2Q 1212 Numerical Example: Negative Externalities • Assume the steel firm faces the following MB and MPC curves: MB = 300 − Q MPC = 20 + Q • Assume the fishery faces the following MD curve: MD = 40 + 2Q