To calculate the amount of interest that Catelyn's investment will earn over a certain period of time, you can use the compound interest formula: A(t) = p(1 + i)^t, where A(t) is the amount of the investment after t years, p is the initial amount of the investment, and i is the interest rate.
For example, if Catelyn invests $7,000 at an interest rate of 5.6% compounded annually, the amount of interest earned after 1 year can be calculated as follows:
A(1) = $7,000(1 + 0.056)^1 = $7,392
This means that after 1 year, Catelyn's investment will be worth $7,392, including the interest earned.