Riddle Answers

2. "If I asked the other guard, which door would he indicate leads to Paradise?" Take the door opposite to what's indicated. Regardless of whom you ask, they'll point to the wrong door.

3. Ten is three. There are three letters in ten, three letters in one, four letters in zero.

4. Look at the factorizations of 36: (36,1,1), (18,2,1), (9,4,1), (9,2,2), (6,6,1), (6,3,2), (4,3,3). All these add to distinct sums except 9+2+2 = 6+6+1 = 13. That must be the first 2 digits of the new family's license plate, or the neighbor would not have needed more information. The fact that the new family has an oldest daughter means the twins must be 2, not 6. So, the daughters are aged 9, 2, 2.