You can put this solution on YOUR website! 11% per year compounded semi-annual;y is equal to 11/2 = 5.5% per semi-annual period.
3 years is 6 semi-annual periods
f = p * (1 + r) ^ n
f is the future value
p is the present value
r is the interest rate per time period.
n is the number of time periods.
formula becomes f = 6400 * (1 + .055) ^ 6
solve for f to get f = 8824.593963