$5648.85
The formula for compound interest is
A = P(1+r/n)^(nt)
where
A = Amount of money at end of period
P = Initial principle
r = Rate of interest
n = number of compound periods per yet
t = number of years.
So let's plug the numbers into the formula
A = P(1+r/n)^(nt)
A = 1680(1+0.0825/2)^(2 * 15)
A = 1680(1 + 0.04125)^30
A = 1680(1.04125)^30
A = 1680(3.362408)
A = $5648.85
