Based on the information given the amount of their tax liability is $9,022.
Since their taxable income is $78,500 in order to determine Amy and Ethan tax liability we would be using the tax rate schedules which is 12%)
Hence,
Tax liability=$1,990 + [($78,500 - $19,900) x 12%]
Tax liability=$1,990($58,600×12%)
Tax liability=$1,990+$7,032
Tax liability= $9,022
Inconclusion the amount of their tax liability is $9,022.
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