Problem 6 · 2010 Math Kangaroo
Medium
Spatial & Visual Reasoning
spatial-reasoning
In the box are seven blocks. You want to rearrange the blocks so that another block can be placed in the box. What is the minimum number of blocks that have to be moved?
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Answer: B — 3
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Hint 1 of 2
You only need enough free space for one more block of the same kind.
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Hint 2 of 2
Try to clear the smallest set of blocks that opens up a gap big enough.
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Approach: find the fewest blocks to relocate to free a slot
- Look for where an eighth block could fit and what currently blocks it.
- Shifting the blocks around that spot, the minimum that must be moved is 3.
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