What is the puzzler about hallway lights? The first person turns them all on, and the next person pulls every other chain, and the next person pulls every third chain and so on, till all lights are eather on or off.
The question is, which lights are on and which lights are off. Are you asking for the answer?
They’re just silly little math problems that never occur in real life so I don’t think about them. Like when will the two trains meet if one is going 30 and the other 50? What idiot would want them to meet?