the initial concentration of the compound, chemistry homework help

co(NH3)5Br2+ has a rate constant of 6.3*10^-6 s-1 and the initial concentration of this compound is 0.100 M.This is what I have done..ln[A]t=-kt + ln[A]oln[A]t=-(6.3*10^-6)(6.48*10^-4)+ln[.100]=1.89 M. But this wrong. The answer is .066 but I don't understand why.