Hammad Shaikh

CAT Preparation Community 5y ago

.9 dwarfs numbered and tagged 1-9 are crossing a passage guarded by a devil. An old wizard comes to their rescue by bringing a shuttle of his own. This shuttle can only take three dwarfs at a time. And shuttle does not move if there is no one sitting inside. After each trip, one dwarf has to travel back and fetch the others. The devil challenges the old wizard but agrees to let the shuttle pass on two conditions. 1. The sum of numbers of dwarf identity tags traveling at any time must be a square number. 2. The old wizard and the devil will not make any trips on the shuttle. Dwarfs strategize their travel plans to minimize the number of trips they would need to make and pass the passage as soon as they can. How many trips do they need to make?Class 7 ka hh baad mein krna..Class 7 ka hh baad mein krna..