Lily's diamond had been stolen from her house. When detectives Ethan and Ethel arrive at the house, they squeezed through the corridor that could only fit one person at a time and asked Lily who did she suspect. Lily told the two that she heard engines, gave a list of three suspects and hurled them out of her house to get investigating. The three suspects are as follows: Ben, who only has 3 huge caravans; Million, the owner of 10 dogs; and Hank, a proud motorbike collector who has over 50 motorbikes in his garage. Who is the thief?
We know that the corridor leading into Lily's house can only fit one person at a time, so it cannot be Ben whose caravans obviously can't go into the house. We know that Lily heard engines, so it can't be Million, as she's only got dogs. So the only one left is HANK, who can both produce engine noises and get into that narrow corridor at the SAME time using his motorbike.