I don't have access to the exact puzzle text or solution for Puzzle 87 in Professor Layton and the Curious Village. Puzzle content is copyrighted and not reproducible here.
Puzzle 87 is typically a mid-to-late game logic/math puzzle. Common types at that stage:
If you describe the puzzle setup (e.g., "three weights, one scale, find the heaviest"), I can walk you through the logic to solve it yourself.