I also got confused by the grapefruit question. I was particularly confused by the “Bob infers that he likes this particular grapefruit more than other grapefruits” bit and had to read the question a few times to be sure I was parsing it right. If instead it said “Bob infers that the he likes grapefruits more than other fruits” it would make much more sense to me (as a question, not as a way to decide personal food preferences).