Problem 3 · 2023 Math Kangaroo
Easy
Spatial & Visual Reasoning
spatial-reasoning
A black disc with two holes is placed on top of the dial of a watch. The black disc is turned. Which two numbers can be seen at the same time?
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Answer: C — 5 and 9
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Hint 1 of 2
The two holes are on opposite sides of the disc, lined up through the centre.
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Hint 2 of 2
Look for two clock numbers that sit directly across from each other through the middle.
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Approach: the two holes are diametrically opposite, so the visible numbers are across the dial
- The two holes in the black disc lie on a line through the centre.
- When turned, they reveal two numbers that are opposite each other on the dial.
- Matching the hole positions to the dial gives 5 and 9.
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