Problem 12 · 2017 Math Kangaroo
Medium
Spatial & Visual Reasoning
paper-cuttingfolding
Bob folds a piece of paper, then punches a hole into the paper and unfolds it again. The unfolded paper then looks like this. Along which dotted line has Bob folded the paper beforehand?
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Answer: C
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Hint 1 of 2
Count the holes: four holes from one punch means the paper was in four layers.
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Hint 2 of 2
Four layers come from folding twice, along both centre lines.
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Approach: four holes need four layers, i.e. folds along both centre lines
- One punched hole makes one hole per layer of paper.
- Four holes mean the paper had four layers when punched.
- Four layers come from folding along both the horizontal and the vertical centre line.
- That double fold is shown by the cross in choice C.
Mark:
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