I just applied logic to see around the typo it appears some were unable to.
Just out of interest, how come the logic you applied to 'see around the typo' got you a different answer to their's (which was 338ft)?
Only asking, as they say.
As you observed, it was a pretty simple question ... so the inability of an instructor to distinguish between QFE and QNH seems rather fundamental, especially after the error he was making had been pointed out on several occasions.