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Bridge Crossing
GoogleJane Street
Four people must cross a bridge at night with one flashlight. They take 1, 2, 5 and 10 minutes to cross. At most two cross at once, and a pair moves at the slower person’s pace; the flashlight must be walked back each time. What is the minimum total time (minutes)?
Approach
Get the two slowest across together.
Use the fastest two as shuttles.
Answer
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The answer is 17. Sign in free for the full worked solution and to check your own answer.
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