Mathematics · Logical Reasoning

There are five rooms in a house — a hall, kitchen, study room, bedroom, and dining room. There is one light in each room. The following conditions apply: 1. Whenever the kitchen light is on, the study room light is off. 2. Whenever the dining room light is on, the kitchen light is also on. 3. Whenever the study room light is on, the hall light must be on. How many lights, at the most, can be turned on simultaneously?