Problem 5 · 2022 Math Kangaroo
Medium
Spatial & Visual Reasoning
sequence-of-figures
Karin places tables of size \(2\times 1\) according to the number of participants in a meeting. The diagram shows the table arrangements from above for a small, a medium and a large meeting. How many tables are used in a large meeting?
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Answer: C — 12
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Hint 1 of 2
Don't compute a formula — just see how many tables get added from one meeting to the next.
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Hint 2 of 2
The small, medium and large arrangements grow by the same number of tables each step.
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Approach: spot the constant jump in the number of tables
- Count the \(2\times 1\) tables in the small and medium arrangements: they go 4, then 8.
- Each step up adds the same number of tables (4 more), so the next arrangement has \(8+4\).
- The large meeting therefore uses \(12\) tables, which is answer C.
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