AMT Computation. William and Maria Smith are a married couple filing jointly. They have no children and report the following items in 2018:

Taxable income...........................................................................$100,000
Tax preferences...............................................................................20,000
AMT adjustments related to itemized deductions......................30,000
Regular tax liability...........................................................................13,879

a. What is the Smith's AMT liability?

b. What would be William's AMT liability if he were an unmarried taxpayer filing single with a regular tax liability of $18,290?