Answer:
a. Erwin and Eleanor are married and file a joint tax return. They have adjusted gross income of $36,000, no tax-exempt interest, and $12,400 of Social Security benefits. As a result, $ of the Social Security benefits are taxable.
b. Assume Erwin and Eleanor have adjusted gross income of $12,000, no tax-exempt interest, and $16,000 of Social Security benefits. As a result, $ of the Social Security benefits are taxable.
c. Assume Erwin and Eleanor have adjusted gross income of $85,000, no tax-exempt interest, and $15,000 of Social Security benefits. As a result, $ of the Social Security benefits are taxable.