text: i'm confused? the amount a in an account after t years from an initial principle p invested at an annual rate r compounded continuosly is given by a=pe^(rt) where r is expressed as a decimal.  solve this formula for t in terms of a,p, and r you need to take the natural log of both sides to solve for t.    a = pe^(rt)  ln(a) = ln(pe^(rt))  ln(a) = ln(p) + ln(e^(rt))  ln(a) = ln(p) + rt  rt = ln(a) - ln(p)  rt = ln(a/p)  t = (1/r) ln(a/p)  hope that helped!  ~ ♥ ~