In the greentext, the question is posed: which is better, small boobs or large boobs? Rather than explicitly telling the man "neither is better," the Great Philosopher uses a metaphor to help the man come to that understanding himself. The subtext is that it's an invalid question; despite their differences, neither is better, just as $30 in coins has the same monetary value as $30 in bills.
The ability to recognize when a question is itself invalid is important to reading comprehension, and you cannot fully understand a concept if you aren't capable of declining to take statements about it at face value. You may have read that it isn't possible to influence the roll of a die before that test, or you may have assumed that it isn't, but if simply seeing the question "how can you influence the roll of a fair die" makes you think that it must be possible, then you didn't understand that it isn't. Had you had better reading comprehension at that time, you may have been able to answer the question correctly without any further context needed. All you needed to do was not assume that the question had an answer.
Of course, that's not very appropriate for a math class. Better to teach students that in... Social studies? It's been such a long time since I've been in school, I can't even remember what class is meant to teach literacy.