To simplify the expression \( t^{400} t^{100} \) using the Quotient Rule of Integer Exponents, we will actually apply the Product Rule of Integer Exponents, as the expression involves multiplication of terms with the same base.
The Product Rule states that when multiplying two powers with the same base, you add the exponents:
\[ t^m \cdot t^n = t^{m+n} \]
In this case:
\[ t^{400} \cdot t^{100} = t^{400 + 100} = t^{500} \]
Therefore, the simplified expression is:
\[ t^{500} \]