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2011 Math Kangaroo

Problem 15

Problem 15 · 2011 Math Kangaroo Medium
Spatial & Visual Reasoning path-tracingspatial-reasoning

In each square of the maze there is a piece of cheese. Ronnie the mouse wants to enter and leave the maze as shown in the picture. He doesn’t want to visit a square more than once, but would like to eat as much cheese as possible. What is the maximum number of pieces of cheese that he can eat?

Figure for Math Kangaroo 2011 Problem 15
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Answer: C — 37
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Hint 1 of 2
Plan a single path from the entrance to the exit that never revisits a square.
Still stuck? Show hint 2 →
Hint 2 of 2
Try to weave through as many squares as the walls allow before leaving.
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Approach: trace the longest non-repeating path
  1. Starting at the entrance, follow the corridors so the path never crosses itself.
  2. The walls let the mouse snake through at most 37 of the squares before reaching the exit.
  3. So the greatest number of cheese pieces he can eat is 37.
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