Need some help please. I tried 7,280, 12,160 and 12,376 are all wrong

Determine the taxable amount of social security benefits for the following situations. If required, round your answers to the nearest dollar. If an amount is zero, enter "O". a. Erwin and Eleanor are married and file a joint tax return. They have adjusted gross income of $41,600, no tax-exempt interest, and $14,560 of Social Security benefits. As a result, $ 7,280 X of the Social Security benefits are taxable. b. Assume Erwin and Eleanor have adjusted gross income of $16,400, no tax-exempt interest, and $18,040 of Social Security benefits. As a result, $ 0 of the Social Security benefits are taxable. c. Assume Erwin and Eleanor have adjusted gross income of $100,000, no tax-exempt interest, and $15,000 of Social Security benefits. As a result, $1 12,750 of the Social Security benefits are taxable