Problem 6 · 2022 Math Kangaroo
Medium
Spatial & Visual Reasoning
path-tracing
All vehicles in the garage can only drive forwards or backwards. The black car wants to leave the garage (see diagram). What is the minimum number of grey vehicles that need to move at least a little bit so that this is possible?
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Answer: C — 4
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Hint 1 of 3
Find the exit first, then the straight lane the black car must drive along to reach it.
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Hint 2 of 3
Only the grey vehicles actually sitting in that lane (or blocking a vehicle that does) need to move.
Still stuck? Show hint 3 →
Hint 3 of 3
Count just those blockers - vehicles parked out of the way can stay put.
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Approach: clear the black car's exit lane, moving only the blockers
- The black car must drive straight to the opening on the right.
- Identify every grey vehicle sitting in or across that path.
- Exactly 4 of them must shift at least a little to free the route.
- So the answer is C.
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