Answer:
without tax: $ 7 consumer surplus
with tax: $ 2 consumer surplus
differece: decrease of $5
Explanation:
the consumer surplus is the difference between the amount willing to pay for the good and the equilibrium price:
with no tax:
ken is willing to buy for 20 - 15 equilibrium price = 5
mark is willing to buy for 17 - 15 equilibrium price = 2
total 7
with taxes:
ken is willing to buy for 20 - 18 equilibrium price = 2
mark has no consumer surplus
total 2
difference: 5
