How to solve question b mathematically

8. The market for scallops is described in the following table: Price Quantity Quantity Quantity Supplied Supplied per Demanded (before (after kilo tax) tax) $20 600 400 22 550 450 24 500 500 26 450 550 28 400 600 30 350 650 a) Before the tax, what are the equilibrium price and quantity? b) Fill in the Quantity Supplied (after tax) column assuming that a $4 per kilo excise tax is put on the product. c) What are the new equilibrium price and quantity