Solution :
The diagram depicts the market for Marijuana where DD represents the demand curve and SS represents the supply curve and initial equilibrium occurs at the point [tex]E_1[/tex], where [tex]P_1[/tex] is the initial equilibrium price and [tex]Q_1[/tex] is the initial equilibrium quantity.
An excise tax on marijuana sales will increase the cost of the production of marijuana and shift the supply curve leftwards to S+tax with new equilibrium at point [tex]E_2[/tex] where the equilibrium price of marijuana has increased to [tex]OP_2[/tex] and equilibrium quantity of marijuana has decreased to [tex]OQ_2.[/tex]