Acimera is a small country currently importing goods A, B and C. Each unit of good A produced requires 3 units of good B and 4 units of good C. The current world prices of the three goods are: P (A) = 800, P (B) = 40 and P(C) = 30. The government imposes the following tariffs: 20% on good X, 40% on good B and 50% on good C. Calculate the effective rate of protection for good A.