Suppose an Egyptian mummy is discovered in which the amount of carbon-14 present is only about three-fifths the amount found in living human beings. The amount of carbon-14 present in animal bones after $t$ years is given by $y=y_{0} e^{-0.0001216 t}$, where $y_{0}$ is the amount of carbon-14 present in living human beings. About how long ago did the Egyptian die?

Step 1 ：We are given that the amount of carbon-14 present in the mummy is three-fifths the amount found in living human beings. This means that \(y = 0.6y_{0}\).

Step 2 ：We can substitute this into the given equation \(y=y_{0} e^{-0.0001216 t}\) and solve for \(t\).

Step 3 ：Let \(y0 = 1\) and \(y = 0.6\), we can solve the equation to find \(t\).

Step 4 ：After calculation, we find that \(t = 4200.868616496634\).

Step 5 ：Rounding to the nearest whole number, we get \(t = 4201\).

Step 6 ：Final Answer: The Egyptian mummy died approximately \(\boxed{4201}\) years ago.