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Puzzle | Couples crossing the river

  • Difficulty Level : Medium
  • Last Updated : 26 Aug, 2017

Three couples are on the vacation.They need to cross the river to reach their hotel. There are 3 rules which are as follows:-
Rule 1:- The boat can only carry two people at a time. If the third person trying to get in the boat then the boat will sink.
Rule 2:- The husbands are so jealous that they can not let their wife with another man, without their presence.
Rule 3:- The boat cannot run on itself. At-least one person should be on the boat to go from one side to another.

How many trips does it take them to all get across the river?
Note:The couples can be identified by their matching color clothes and there is no other way of going to hotel.


Solution:

Let the 3 couples have wore green, red and blue dresses.So, there should be green wife and green husband, red wife and red husband, blue wife and blue husband.
Step 1:-Green couple will go to the hotel side and green husband will return with the boat.(2 moves)
Step 2:-Now red wife and blue wife will go to the hotel side and red wife will return with the boat.(2 moves)
Step 3:-Green husband and blue husband will go to the hotel side and blue couple will return with the boat.(2 moves)
Step 4:-Red husband and blue husband will go to the hotel side and green wife will return with the boat.(2 moves)
Step 5:-Red wife and blue wife will go to the hotel side and blue wife will return with the boat.(2 moves)
Step 6:-Finally, blue wife and red wife will go the hotel side.(1 move)

So, there will be a total of 11 steps.

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