Problem 5 · 2022 Math Kangaroo
Easy
Spatial & Visual Reasoning
path-tracingreflection
When a laser beam hits a mirror it changes direction (see the small diagram). Each mirror reflects on both of its sides. At which letter does the laser beam come out?
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Answer: B — B
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Hint 1 of 3
Put your finger where the beam starts and slide it along, but turn a corner every time you reach a slanted mirror.
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Hint 2 of 3
A mirror leaning like '\' turns a beam going across into a beam going down; a mirror leaning like '/' turns it the other way.
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Hint 3 of 3
Keep sliding and turning until your finger walks off the edge at one of the letters.
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Approach: trace the beam one mirror at a time
- Start your finger on the beam and slide it straight until it touches the first slanted mirror.
- At each mirror, make a quarter turn the way the mirror leans, then keep sliding.
- Following every bounce, the finger leaves the grid at the letter B.
Mark:
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