A = amount to become = 3205.09
P = principal = beginning amount = 2500
r = 5% = 0.05
n = 4 since compounding is quarterly, 4 times a year.
Divide both sides by 2500
Take natural logs of both sides
Move the exponent 4t in front of the natural log
Solve for t by dividing both sides by 4*ln(1.0125)
Round to t=5 years
Edwin