Hard
Physics Riddles
13 XP

The Bridge Crossing

18,094 solved 72% solve rate 28% fail rate
Four people must cross a bridge at night with one flashlight. They can cross in 1, 2, 5, and 10 minutes. Two cross at a time at the slower person's pace. What is the fastest total time?
Only 72% solve this correctly
18,094 attempts
Earn +13 XP for solving
Quick Answer & Explanation
17 minutes. Strategy: 1&2

The answer to this riddle is 17 minutes. Strategy: 1&2. Difficulty: Hard · Solved by 18,094 puzzle lovers.

17 minutes. Strategy: 1&2 cross (2min), 1 returns (1min), 5&10 cross (10min), 2 returns (2min), 1&2 cross (2min).
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