[Algebra]
Problem: If $\log _{10} x=3+\log _{10} y$, what is the value of $\frac{x}{y}$ ?

Solution: $$
\begin{gathered}
\log _{10} x-\log _{10} y=3 \\
\Leftrightarrow \log _{10}\left(\frac{x}{y}\right)=3 \\
\Leftrightarrow \frac{x}{y}=10^{3}=1000
\end{gathered}
$$

Final answer: 1000