You have $12,000 excess cash to invest after you fully funded your emergency fund. A 9,500 T-bill can be purchased (maturing to value at $12,000 after one year), or you can buy three --$4000 CD that can be purchased with a guaranteed 5% return after 12 months. Which will give a better return (in percentages)? Please fully explain the process. I'm confused on which equations to use.