# Need help solving this river puzzle

**URL:** <https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043>\
**Category:** Miscellaneous and Personal Stuff I Must Share\
**Created:** [December 19, 2003, 8:27pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043 "2003-12-19T20:27:35Z")\
**Posts on this page:** 10\
**Page:** 1

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**Author:** ![DirtyKash](https://avatars.discourse-cdn.com/v4/letter/d/57b2e6/32.png) [@DirtyKash](https://boards.straightdope.com/u/DirtyKash)\
**Post date:** [December 19, 2003, 8:27pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043/1 "2003-12-19T20:27:35Z")

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\>\>\> [CLICK HERE](http://smallcampus.net/html/maths_games/2001-05-03/riverIQGame.swf) \<\<\<

I have trouble solving this puzzle…

Here are the rules to the game:  
**Everybody** has to cross the river, but the following rules apply:

1. Only 2 people on the raft at a time.
2. The father cannot stay with any of the daughters without the mother being there.
3. The mother cannot stay with any of the sons without the father being there
4. The thief (wearing a striped shirt) cannot stay with **any** family member unless the policeman is with him
5. Only the Father, the Mother and the Policeman know how to operate the raft, so everytime the raft crosses the river, one of the three has to be crossing.
6. The raft cannot cross by itself, obviously.

When you go to the website click on the **blue** circle at the bottom right… When you’re ready to cross the river, just click on the red knob.

So far, I have…

Police + thief -\>  
\<- Police  
Police + son -\>  
\<- Police + thief  
Man + son -\>  
\<- Man  
Woman + Man -\>  
\<- Woman  
Police + thief -\>  
\<- Man

then I’m stuck… not even sure my steps lead to the right solution.

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**Author:** ![shijinn](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@shijinn](https://boards.straightdope.com/u/shijinn)\
**Post date:** [December 19, 2003, 8:57pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043/2 "2003-12-19T20:57:40Z")

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> [@](#):
>
> Originally posted by \*\*DirtyKash \*\*  
> Police + thief -\>  
> \<- Police  
> Police + son -\>  
> \<- Police + thief  
> Man + son -\>  
> \<- Man  
> Woman + Man -\>  
> \<- Woman  
> Police + thief -\>  
> \<- Man

send the police and thief back -

father mother \>  
\< mother  
mother girl \>  
\< police thief  
police girl \>  
\<police  
police and thief\>

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**Author:** ![Anonymous\_Coward](https://avatars.discourse-cdn.com/v4/letter/a/94ad74/32.png) [@Anonymous\_Coward](https://boards.straightdope.com/u/Anonymous_Coward)\
**Post date:** [December 19, 2003, 8:58pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043/3 "2003-12-19T20:58:25Z")

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Step by step answers in spoiler box below…

Police takes prisoner. Police returns to shore.  
Police takes boy 1. Police and prisoner return to shore.  
Father takes boy 2. Father returns to shore.  
Father takes mother. Mother returns to shore.  
Police takes prisoner. Father returns to shore.  
Father takes mother. Mother returns to shore.  
Mother takes girl 1. Police and prisoner return to shore.  
Police takes girl 2. Police returns to shore.  
Police takes prisoner.

I’m not that smart. I googled the answer 🙂

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**Author:** ![Casey1505](https://avatars.discourse-cdn.com/v4/letter/c/dc4da7/32.png) [@Casey1505](https://boards.straightdope.com/u/Casey1505)\
**Post date:** [December 19, 2003, 8:59pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043/4 "2003-12-19T20:59:35Z")

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I did it. Two hints. The thief goes on the first and last trips.

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**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\
**Post date:** [December 19, 2003, 9:04pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043/5 "2003-12-19T21:04:38Z")

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That’s the funniest game ever. I thought “what would happen if you left the mom and a boy alone? Would the kid get the smackdown?” Lo and behold…

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**Author:** ![Shagnasty](https://avatars.discourse-cdn.com/v4/letter/s/9dc877/32.png) [@Shagnasty](https://boards.straightdope.com/u/Shagnasty)\
**Post date:** [December 19, 2003, 9:09pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043/6 "2003-12-19T21:09:01Z")

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Over: Policeman, Thief  
Back: Policeman  
Over Policeman, boy  
Back Policeman, Thief  
Over: Dad, boy  
Back: Dad  
Over: Mum, Dad  
Back: Mum  
Over: Policeman, Thief  
Back: Dad  
Over: Mum, Dad  
Back: Mum  
Over: Mum, Girl  
Back: Policeman, Thief  
Over: Policeman, Girl  
Back: Policeman  
Over: Policeman, Thief

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**Author:** ![DirtyKash](https://avatars.discourse-cdn.com/v4/letter/d/57b2e6/32.png) [@DirtyKash](https://boards.straightdope.com/u/DirtyKash)\
**Post date:** [December 19, 2003, 9:09pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043/7 "2003-12-19T21:09:07Z")

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Thank you guys! Finally… the puzzle has been solved. This has been bugging me for days, I seriously couldn’t sleep.

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**Author:** ![Casey1505](https://avatars.discourse-cdn.com/v4/letter/c/dc4da7/32.png) [@Casey1505](https://boards.straightdope.com/u/Casey1505)\
**Post date:** [December 19, 2003, 9:10pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043/8 "2003-12-19T21:10:29Z")

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How long did it take everyone? Took me about 20 minutes.

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**Author:** ![shijinn](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@shijinn](https://boards.straightdope.com/u/shijinn)\
**Post date:** [December 21, 2003, 5:45pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043/9 "2003-12-21T17:45:34Z")

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i didn’t time myself, but it was easy when i realised from following the OP’s steps that both father and mother would not be able to bring the last girl back.

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**Author:** ![Red\_Matrix](https://avatars.discourse-cdn.com/v4/letter/r/34f0e0/32.png) [@Red\_Matrix](https://boards.straightdope.com/u/Red_Matrix)\
**Post date:** [December 22, 2003, 5:42pm UTC](https://boards.straightdope.com/t/need-help-solving-this-river-puzzle/220043/10 "2003-12-22T17:42:27Z")

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It took me about 10 minutes. I’ve never done the river puzzle with so many people… it was only with 3.

FD