The correct answer to this question is 36%. With the information given, we know that 64% of the Chinese population has unattatched earlobes. Those with these earlobes are the dominant group. This means that the answer must be under 64%. A percentage is complete at 100%, so we can subtract 64 from 100, to give us 36% as the answer.
This type of question would be found on a math test and is fairly simple to answer if one reads and calculates correctly. This question could also be found on a SAT, to test one's understanding of mathematics and reading comprehension skills.