Find the equilibrium price and quantity in this economy the

Question

Suppose an economy with the following supply and demand: Qs = 30p

Qd =300-20p

1. Find the equilibrium price and quantity in this economy
2. The government thinks that the price this good is too high, so it imposes a price equal to 4. What is the quantity supplied and demanded? What is the deadweight loss? Explains what would happen in this economy.
3. After failing with its first policy, the government decide to subsidy the demand in order to get a price equal to 4. The government will give a fix amount in order to move the supply curve and achieve a price equal to 4. What is the subsidy that reaches government's objective? What is the total cost for the government? What is the deadweight loss?