Identify the one illogical comparison among the following examples. That racer is 18 months older than the others on the team. The quickest runner on our team beat me by 30 seconds. She runs more fast?

The illogical comparison is "She runs more fast." The correct phrase should be "She runs faster," as "fast" is an adverb that does not require "more" for comparison. The other examples provide clear comparisons without grammatical errors.