To simplify the expression \( t^{400} t^{100} \) using the Quotient Rule of Integer Exponents, remember that when multiplying terms with the same base, you add the exponents:
\[ t^{a} \cdot t^{b} = t^{a + b} \]
In this case:
\[ t^{400} \cdot t^{100} = t^{400 + 100} = t^{500} \]
So the simplified expression is:
\[ t^{500} \]