Comment by mcphage

I'm not sure I understand. In the 4 card case, there are 4! or 24 different arrangements. So a total of ~4.5 bits. Each question gives you at most 1 bit of information. So it would seem like it takes up to 5 questions, but the page repeatedly says "you can always find which card is which in under 5 questions". Is there a technique I am missing?