A perfectly competitive industry faces domestic demand $q_{d} 5100-p$ and has the industry supply curve $q_{s} 5401 p$. (a) If the world price is $£ 50$, what is the value of net exports? (b) If the world price is $£ 20$, what is the value of net exports? (c) In the absence of trade, what is the equilibrium domestic price? (d) At a world price of $£ 20$, suppose the government levies a tariff of $£ 5$ per unit. Calculate the value of tariff revenue and the total value of the two deadweight loss triangles.