Suppose there's a single terraced street that contains 19 houses. The postman notices that no 2 adjacent houses ever receive mail on the same day, and that no more than 2 adjacent houses don't receive mail on any day. What is the maximum number of days he can deliver before repeating the pattern? 3. The attempt at a solution well, there are a maximum of 10 deliveries he can make, starting at house 1 then missing a house and delivering to house 3 etc. And he can make a minimum of 6 deliveries There is only 1 way to deliver to 10 houses, but after that my methods start to fall apart!! any one got any insight that can help?