$1.$ Equilibrium quantity Q$=8000,$ equilibrium price P$=20.$ Demand elasticity is $-1\mathrm{.}5$ Supply

elasticity is $+1\mathrm{.}2$

a$.$ Reconstruct linear demand and supply functions

b$.$ Pick on of the interventions and analyze the impact:

i$.$ A price floor at P$=22$

ii$.$ A price ceiling at P$=18$

iii. A tax of $4$ per unit

iv$.$ A subsidy of $2$ per unit