To calculate compound interest, we use a special formula. We plug values into A = P(1 + r/n)^{nt} to get our compound interest.
In the formula, A is the amount of money at the end. P is our principal amount, or starting value. In this case, it would be $18,000. r is the rate of interest, 6.07% (aka 0.0607) in this case. n is the number of times to compound the interest. In this situation, daily, that would be 365. Finally, t is the amount of time, which is 9 years.
Let's plug it all in:
A = $18,000(1 + 0.0607/365)^{365*9}
A = $18,000(1.00016630137)^{3,285}
A = $31,081.92
After 9 years of compounded daily interest at a rate of 6.07%, we have $31,081.92.