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Dysfunctional Crossing (Posted on 2005-09-26) Difficulty: 3 of 5
There are 8 people that need to cross a river. The water is too deep and fast to walk or swim across, and the only transportation device available is a raft. The raft can only be operated by adults, cannot float across the river on its own, and can carry at most two people.

The 8 people are a juvenile delinquent, her jailer, and a dysfunctional family of six: mother, father, two sons, and two daughters. To be clear, the only adults are the jailer, the mother, and the father.

Unfortunately some people fight with each other:

  • The juvenile delinquent will fight with anybody if her jailer is not present.
  • The father fights with either daughter if the mother is not present to mediate.
  • The mother fights with either son if the father is not present to mediate.
  • How can these 8 people cross the river without any fights? How many trips on the raft did it take?

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      Submitted by nikki    
    Rating: 4.1538 (13 votes)
    Solution: (Hide)
    There are two very similar solutions of 17 trips on the raft. The only difference is if you move the females or the males of the family first. So swap M and F, S1 and D1, and S2 and D2 for the two different solutions.

    I will give the people short names: JD and J are the juvenile delinquent and the jailer, and then we have M, F, S1, S2, D1, and D2.

    Starting Side		Raft Activity	Ending Side
    J JD M F S1 S2 D1 D2	start		no one
    M F S1 S2 D1 D2		J JD cross	no one
    M F S1 S2 D1 D2		J comes back	JD
    M F S2 D1 D2		J S1 cross	JD
    M F S2 D1 D2		J JD come back	S1
    J JD M D1 D2		F S2 cross	S1
    J JD M D1 D2		F comes back	S1 S2
    J JD D1 D2		M F cross		S1 S2
    J JD D1 D2		M comes back	F S1 S2
    M D1 D2			J JD cross	F S1 S2
    M D1 D2			F comes back	J JD S1 S2
    D1 D2			M F cross		J JD S1 S2
    D1 D2			M comes back	J JD F S1 S2
    D2			M D1 cross	J JD F S1 S2
    D2			J JD come back	F S1 S2 M D1
    JD			J D2 cross	F S1 S2 M D1
    JD			J comes back	F S1 S2 M D1 D2
    No one			J JD cross	F S1 S2 M D1 D2
    No one			end		J JD F S1 S2 M D1 D2
    

    Comments: ( You must be logged in to post comments.)
      Subject Author Date
    Hints/TipsNew Linknikki2007-10-08 23:50:56
    SOLUTION I HOPELeigh Lillico2005-12-24 05:45:00
    re(2): dysfunctional crossing ,the solutionshahul2005-12-16 13:00:03
    re: dysfunctional crossing ,the solutionLeigh Lillico2005-12-16 02:51:41
    Solutiondysfunctional crossing ,the solutionshahul2005-12-13 15:19:26
    re: One moreLeigh Lillico2005-12-10 00:45:10
    One more "My Solution" !!Nilesh2005-12-06 08:14:39
    SolutionDysfunctional Crossing Solutionhelen2005-11-18 23:32:36
    SolutionNo SubjectMichael Kornrade2005-11-12 15:41:54
    SolutionNo SubjectYO MAMA2005-11-11 21:05:34
    ?? for nikkiLeigh Lillico2005-11-05 17:45:04
    MY SOLUTIONLeigh Lillico2005-10-29 02:38:21
    re: No SubjectNina2005-10-06 05:02:31
    No SubjectNina2005-10-06 04:59:41
    re(2): a better solutiontrevor2005-10-02 22:24:22
    re: a better solutionignatious2005-10-02 20:05:01
    re: a better solutionBractals2005-10-02 16:25:06
    a better solutiontrevor2005-10-02 16:07:09
    solutionignatious2005-10-02 08:12:50
    i knowOrlando2005-09-29 19:25:11
    Solutionre(2): Finally--a computer solution--the corrected programCharlie2005-09-28 13:54:43
    re: Finally--a computer solution--bugCharlie2005-09-28 13:07:17
    maybe thischard2005-09-28 10:39:27
    SolutionFinally--a computer solutionCharlie2005-09-28 02:24:47
    SolutionSolutionBractals2005-09-27 21:32:57
    No SubjectMike2005-09-26 20:55:40
    SolutionSolutionKen Schelper2005-09-26 20:20:45
    re(2): hmm...Kristi2005-09-26 20:19:39
    re: hmm...olin2005-09-26 20:13:03
    Solutionhmm...Kristi2005-09-26 19:39:29
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