Tim and Tammy are the same age and have greatly enjoyed their life. They began taking Social Security benefits in 2016 at age 67 and are living off their benefits and a small amount ($1,050) of municipal bond interest. They have been able to save money in an IRA which they have contributed to over the years. The balance at the end of 2020 was $640,000. 1. Assuming their combined Social Security benefits are $36,500 in 2021, how much of their Social Security benefit is taxable? How much federal income tax do they have for 2021? Only consider their municipal bond income and their Social Security.