The Potions Logic Puzzle

Harry took three quick steps to the left. The White King removed his crown and tossed it at Harry's feet. The White Chess Pieces bowed and slid aside, clearing a path to the door. Black had beaten white!

Hermione and Luo Bin ran to the edge of the chessboard, helped Ron to one side, and carefully checked his injuries.

"He's unconscious, but it's nothing serious. Should one of us stay here with him, or..."

"No, Luo Bin. You were right earlier. We can't let Ron's sacrifice go to waste. Let's hurry to the next challenge!"

"Professor Sprout must have set the Devil's Snare, Professor Flitwick the Flying Keys, and Professor McGonagall the chessboard. That leaves three challenges set by Professor Quirrell, Snape, and Professor Dumbledore. We have to hurry!"

Harry glanced at Ron, his voice anxious.

"Right. Let's go through that door!"

The three reached the door and pushed it open together!

A dizzying stench rushed up their noses. Xiao Ying pinched her nose and burrowed into her master's pocket. Luo Bin pulled out three extra-thick masks, and only after putting them on did they cautiously inspect the room.

It was enormous, more than three times the size of the chessboard chamber. Dark purple claw marks and fist-shaped dents covered the walls. On the floor... lay an adult Troll!

This Troll was much bigger than the one they had encountered on Halloween. A fist-sized bloody lump rose from its pointed head, clearly the reason it lay unconscious.

"Great! We don't have to fight anything here. Let's hurry to the next challenge!"

Hermione leaped over the Troll's thick leg and opened the next door. Harry and Luo Bin jumped over after her.

Luo Bin would have liked to fight the Troll, though. What boy didn't dream of a thrilling battle?

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