Compute the additionalMedicare tax for the following taxpayers. If required, round your answers to the nearest dollar. a. Mario, who is single, earns wages of $440,000 in 2018. His additional Medicare tax is $. b. George and Shirley are married and file a joint return in 2018. During the year, George earns wages of $138,000, and Shirley earns wages of $210,000. Their additional Medicare tax is $.