e^{0.4993·t} = e^{0.4993·(t - 1)} + 1.5
e^{0.4993·t} - e^{0.4993·(t - 1)} = 1.5
e^{0.4993·t} - e^{0.4993·t - 0.4993} = 1.5
e^{0.4993·t} - e^{0.4993·t}·e^{-0.4993} = 1.5
e^{0.4993·t}·(1 - e^{-0.4993}) = 1.5
e^{0.4993·t} = 1.5/(1 - e^{-0.4993})
0.4993·t = ln(1.5/(1 - e^{-0.4993}))
t = ln(1.5/(1 - e^{-0.4993}))/0.4993 = 2.682349778