He said his gf didn't teach him the questions, that doesn't mean he didn't do some studying on his own. If he isn't lying about being Tokyo University level (that's Japanese equivalent of Ivy League btw) you've got some batman level prep going on. I doubt he has trouble with any high school level tests regardless of how little he studies.
EDIT: Also what a reward, being able to give her a piggyback(err piggyshoulder?). x3