Solve for P in the scientific formula PV = nRT

Years = log(total / principal) / n*log(1 + rate/n)
Years = log (25,900 / 4,500) / 4 * log (1 + .071 / 4)
Years = log ( 5.7555555556 ) / 4 * log ( 1.01775)
Years = 0.76008725031 / 4 * 0.0076411110514
Years = 0.76008725031 / 0.0305644442
Years = 24.8683485077
Years = 24.87 (rounded to nearest hundredth)

Source:
http://www.1728.org/compint3.htm