Problem 2 · 2022 Math Kangaroo
Easy
Spatial & Visual Reasoning
path-tracing
Eva paddles her boat around five buoys (see diagram). Which buoys does she paddle around in an anti-clockwise direction?
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Answer: E — 1 and 3
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Hint 1 of 3
Trace the boat's path slowly with your finger and notice which way it curves around each buoy.
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Hint 2 of 3
Anti-clockwise means turning the same way the hands of a clock run backwards; check each buoy for that turn.
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Hint 3 of 3
A buoy is rounded anti-clockwise when the boat keeps it on its left as it loops around.
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Approach: trace the route and watch which way the boat curves around each buoy
- Put your finger on the boat and follow the drawn line all the way around.
- Each time you loop a buoy, ask: am I curving like a clock (clockwise) or backwards (anti-clockwise)?
- Doing this for all five buoys, only buoys 1 and 3 are looped backwards (anti-clockwise).
- So the answer is E.
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