8. Given that $x$ and $y$ are non-negative integers, satisfying $27x + 35y \leq 1000$. Then the maximum value of $xy$ is $\qquad$
8.252

Analysis: By the AM-GM inequality $1000 \geq 27 x+35 y \geq 2 \sqrt{945 x y}$, and since $x, y$ are integers, we know $x y \leq 264$, and at this point $x \approx 18.5, y \approx 14.3$. When taking nearby integers, $x y$ is larger. Testing each case, it is easy to find that when $x=18, y=14$, $x y=252$ is the largest and satisfies the conditions in the problem.