Challenge 1: The Real Ceiling When MaxRequestWorkers Doesn't Match
ServerLimit x ThreadsPerChild — Solution Walkthrough

The calculation:

ServerLimit x ThreadsPerChild = 16 x 20 = 320

So the real effective concurrency ceiling this server will actually
hit is 320 simultaneous connections, not the 400 written in
MaxRequestWorkers.

Why they don't match:

Per this chapter's own explanation, MaxRequestWorkers can never
exceed ServerLimit x ThreadsPerChild -- that product is the true
hard ceiling of the process/thread pool Apache can ever build.
Setting MaxRequestWorkers to a number ABOVE that product (400 is
above 320 here) doesn't raise the real ceiling at all; Apache simply
enforces the lower number silently, without an error or a warning
that the configured 400 is unreachable. Someone reading only the
config file would reasonably expect a ceiling of 400, but the real
number the server can ever actually reach is 320.

WHY THIS WORKS AS AN ANSWER
------------------------------
This exercise checks that the reader understands MaxRequestWorkers is
not an independent, freestanding cap -- it is itself bounded by
ServerLimit x ThreadsPerChild, and a value set above that product is
silently capped down rather than honored, exactly as this chapter's
own text warns.