Answer:
information about the initial situation is missing, so I looked for similar questions and found the attached image:
The government already imposes a $20 tax per bottle of gin, which has already reduced the equilibrium quantity to 40 bottles (down from 50) and increased the demand price to $60.
If the government imposes another $20 tax, it will decrease the quantity even further to 20 bottles of gin and the price will increase to $80.
The government's revenue from the original tax = $20 x 40 = $800.
Government's revenue after the new tax = $40 x 20 = $800. Even though the government's revenue is still the same, consumer and supplier surplus has decreased dramatically.
