First, I assume you mean an ECL 15 drow paladin, who is actually 13th level, right? Otherwise, of course.
For the first case, why not then say...
An ECL 11 human (11 class levels) can survive a CL 20 Word of Chaos, why not an ECL 11 drow (9 class levels)?
Or,
An ECL 20 minotaur fighter...