In Nancy Drew: Treasure in the Royal Tower, to get on the Professor’s good side, answer one of her research questions. If you forget the question, or do not want to answer that question, simply ask the Professor for another.
You can find the answers in the elevator on the plaque, and in the two history books in the lobby. Here’s the complete list of questions and their answers:
“What is the model number on the elevator?” Answer = 50964
“How old was Marie Antoinette when she married King Louis?” Answer = 15
“How many days before her 38th birthday was Marie Antoinette executed?” Answer = 17
“On what date was the Bastille prison destroyed during the French Revolution?” Answer = July 14, 1789
“Not counting the towers, how many windows are there on the faces of the castle?” Answer = Trick question, the answer is unknown. Ask the Professor for another question.