Linda and Don are married and file a joint return. In 2015, they received $12,000 in Social Security benefits and $35,000 in taxable pension benefits and interest.

a. Compute the couple's adjusted gross income on a joint return.

b. Don would like to know whether they should sell for $100,000 (at no gain or loss) a corporate bond that pays 8% in interest each year and use the proceeds to buy a $100,000 nontaxable State of Virginia bond that will pay $6,000 in interest each year.

c. If Linda in (a) works part-time and earns $30,000, how much will Linda and Don's adjusted gross income increase?