One thousand dollars is invested in a savings account that pays 9 interest per year. The interest earned after the first year is added to the account. How much interest is earned on the new principal?

If one thousand dollars is invested at an interest rate of 9% per year, the interest earned after the first year would be $90 (calculated as 0.09 x 1000). This interest is added to the principal, making the new principal $1,090. In the second year, the interest earned on this new principal would be $98.10 (calculated as 0.09 x 1090).