Problem 2 · 2015 Math Kangaroo
Easy
Spatial & Visual Reasoning
spatial-reasoning
Florian has 10 identical metal strips, each with the same number of holes. He bolts them together in pairs to make the 5 long strips in the picture. Which of the long strips is the longest?
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Answer: A
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Hint 1 of 2
Each long strip is two short strips laid end to end, sharing a few holes where they overlap.
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Hint 2 of 2
The fewer holes the two short strips share, the further the long strip stretches.
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Approach: compare how much each pair of strips overlaps
- Every long strip is two equal short strips bolted so they share some holes in the overlap.
- Picture sharing only 1 hole versus sharing many: the less the strips overlap, the longer they reach.
- Strip A is the one whose two pieces overlap the least, so it stretches the furthest.
- The longest strip is A.
Mark:
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