Comparing Values of x and y in an Equation

Let $x$ and $y$ be two positive integers such that the equation $3x + 5y = 30$ holds true. Determine the values of $x$ and $y$. Specifically, compare the two quantities below:

Quantity A: The value of $x$ when $y = 3$.

Quantity B: The value of $y$ when $x = 5$.