Tom, who is age 35 and single, is not covered by a pension plan at work. He plans to retire at age 72. Should he make annual contributions to a regular IRA or a Roth IRA? He expects to earn an annual rate of return on his contributions of 4%, expects to be in the 24% bracket during his employment years, and expects to be in the 22% bracket during his retirement years. [ Hint: assume the contribution to the Roth account equals the contribution to the regular IRA x (1- marginal tax rate).] How would your answer change if he expects to be in the 24% marginal tax bracket when he retires? How would your answer change if he expects to be in the 32% marginal tax bracket when he retires? need the excel calculations as well for the answer.