Question 78
A class has $48$ students, with more city students than students from elsewhere. Students from elsewhere always answer truthfully, while city students may answer truthfully or falsely. When the class moves to a new building, the teacher wants to learn where every student comes from. The teacher may ask any student “Where does that student come from?” and may also ask a student about themself. What is the exact minimum number of questions needed to guarantee identifying where every student comes from?