Multiple choice general knowledge math & puzzles

A B C D _________ 10 5 2 1(secs) A B C D have to cross the bridge only two at a time in dark night with single torch. what is minium time to cross all?

  1. 18

  2. 17

  3. 19

  4. 15
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

To minimize time: 1 & 2 cross (2s), 1 returns (1s), 5 & 10 cross (10s), 2 returns (2s), 1 & 2 cross (2s). Total: 2+1+10+2+2 = 17 seconds. This strategy ensures the slowest people cross together to save time.

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