An Egyptian mummy is discovered in which the amount of carbon-14 present is only about 1/5th the amount found in living human beings.The amount of carbon-14 present in animal bones after t years is given by y=y(0)e^-0.000126t, where y(0) is the amount of carbon present in living human beings. About how long ago did the Egyptian die? Solution y = y(0) / 5 y(0) / 5 = y(0) * e^(-0.000126t) t = ln 5 / 0.000126 = 12773.31 years.