With a suitable diagram, determine producer and consumer surpluses for a product characterized by D = 80−P, S=2P−100. Calculate the deadweight loss of imposing a per unit tax of £7.50.

b)

i) At the initial equilibrium price, the area that represents producer surplus is the area above the supply curve and below the equilibrium price $P_1$, up to the quantity $Q_1$.
Producer surplus: $\boxed{\text{d + f}}$

ii) After the price ceiling is imposed at $P_2$, the quantity traded is $Q_2$.
The area that represents consumer surplus is the area below the demand curve and above the price ceiling $P_2$, up to the quantity $Q_2$.
Consumer surplus: $\boxed{\text{a + b}}$
The area that represents producer surplus is the area above the supply curve and below the price ceiling $P_2$, up to the quantity $Q_2$.
Producer surplus: $\boxed{\text{f}}$

iii) The deadweight loss resulting from the price ceiling is the loss of total surplus due to the reduction in quantity traded from $Q_1$ to $Q_2$. This area is between the demand and supply curves for the quantities no longer traded.
Deadweight loss: $\boxed{\text{c + e}}$