"You want to invest your savings of $20,000 in government securities for the next 2 years. Currently, you can invest either in a security that pays interest of 8% per year for the next 2 years or in a security that matures in 1 year but pays only 6% interest. If you make the latter choice, you would then reinvest your savings at the end of the first year for another year. Why might you choose to make the investment in the 1-year security that pays an interest rate of only 6%, as opposed to investing in the 2-year security paying 8%

Explanation:

In the former case that is investment in security that pays interest of 8% per year for the next 2 years , there is provision of fixed interest rate . That means one can be assured of interest rate of 8 % for two years but he can not get benefit of market fluctuation if interest rate if it  rises above 8 % after one year .

In case of investment in  security that matures in 1 year but pays only 6% interest , one can take the benefit of market fluctuation if interest rate rises above 8 % . So if there is likelihood that interest rate can rise above 8 % in future , one should invest in 6% security for one year and reinvest it after one year , in the same security or in other security which fetches higher rate of interest .

Apart from that , if there is a contingent liability of paying after one year , one can not go in for 2 year security as it will have to break prematurely , that will result in loss of interest .

So due to situation described above,  one should prefer investment in one year security .

you will have $2593.74 in 10 years if you set aside $1,000 at 10%

you will have $9321.91 in 20 years if you set aside $2000 at 8%

you will have $1469.32 in 5 years if you set aside $1000 at 8%

you will have $1296.87 in 10 years if you set aside $500 at 10%

you will have $239.66 in 15 years if you set aside $100 at 6%

you will have $4660.96 in 20 years if you set aside $1000 at 8%