If you save $500 per month into your retirement account between age 20-29 (more precisely, [20, 30)), you will have more money at 65 than if you save $500 per month from 30-64 (more precisely, [30,65)). At what rate of return is this claim true? (You can assume that your contributions are made starting on the day you reach the specified age, and the same day in the subsequent months.)