Confused Bro, Yes U R Dumbed. 1.The census checked the next door. Agree? 2. 36*1*1 (sum=38) 18*2*1 (sum=21) 9*4*1 (sum=14) 9*2*2 (sum=13) 6*6*1 (sum=13) 6*3*2 (sum=11) 4*3*3 (sum=10) Agree? 3. If the sum(=address of next door) was 11 or 21 or 10 or 14 or 38, he doesn't have to be confused. But it must be 13 so that it made him confusion because the sum becomes 13 in 2 different caes as mentioned in 2. 4. Got it? Explorer is absolutely right.