## College Algebra (10th Edition)

$15.27$ years
The amount A after t years due to a principal P invested at an annual interest rate r, expressed as a decimal, compounded n times per year is $A=P\displaystyle \cdot(1+\frac{r}{n})^{nt}$ If the compounding is continuous, then $A=Pe^{rt}$ --- Continuous compounding: $A=Pe^{rt}$ $25,000=10,000e^{0.06t}\qquad.../\div 10,000$ $2.5=e^{0.06t}\qquad.../\ln(...)$ $\ln 2.5=0.06t$ $t=\displaystyle \frac{\ln 2.5}{0.06}\approx 15.27$ years