Since $20 \textbackslash\%=\frac{1}{5}$, multiplying the given condition by 5 shows that $x$ is $30 \cdot 5=(\mathbf{C}) 150$ percent of $y$. 
Suppose $20 \textbackslash\%$ of $x$ equals $30 \textbackslash\%$ of $y$. What percentage of $y$ is $x$ ? (adapted from 2020 AMC 8, Question 15) 
  * $$5$$ 
  * $$35$$ 
  * $$75$$ 
  * $150$ 
  * $$300$$ 