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River Crossing Riddle


RVJ
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There are 8 people (Father, Mother, Thief, Policeman, 2 Sons, 2 Daughters) trying to cross a river by using a raft. Only the adults (excluding the thief) know how to operate the raft. A total of only 2 people are allowed on the raft at any given moment. The raft must travel back and forth across the river in order to pick up all of the people.

 

Rules:

You have the following people trying to cross a river:

 

Father

The father cannot stay with any of the daughters, without their Mother's presence.

Mother

The Mother cannot stay with any of the sons, without their Father's presence.

Thief

The thief cannot stay with any family member, if the policeman is not there.

Policeman

Allowed to travel with everyone.

2 Sons, 2 Daughters

Not allowed to travel without an adult, or be in the presence of the thief without the policeman's supervision. The sons are not allowed to be in the presence of their mother without the supervision of their father. The daughters are not allowed to be in the presence of their father without the supervision of their mother. Both the sons and daughters are allowed to be unsupervised (so long as all other rules are still satisfied).

 

In what sequence must everyone travel in order to get everyone to the other side of the river safely? (Keep in mind that the rules apply at ALL times, and not just on the raft.)

Edited by RVJ
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  • 3 weeks later...

Fun stuff. Think I've got it.

 

 

Let's assign letters for each person: father (F), mother (M), sons (s1 and s2), daughters (d1 and d2), policeman (P), and thief (t), and say they're starting out on the eastern side of a river |.

 

For the first trip, P will take t across and leave him there, since this doesn't appear to violate any rules. P will then return. So it'll be t | P,M,d1,d2,F,s1,s2

 

For the second trip, P will take d1 across and leave her there, but will bring t back across with him so as not to leave d1 and t together: d1 | P,t,M,d2,F,s1,s2

 

For the third trip, M will take d2 across and leave her there, then return: d1,d2 | P,t,M,F,s1,s2

 

For the fourth trip, F and M will go across together, and only F will return: M,d1,d2 | P,t,F,s1,s2

 

For the fifth trip, P will take t across, and M will come back: P,t,d1,d2 | M,F,s1,s2

 

For the sixth trip, F and M will go together, and F will return: P,t,M,d1,d2 | F,s1,s2

 

For the seventh trip, F will take s1 across, and P will return with t: M,d1,d2,F,s1 | P,t,s2

 

For the eighth trip, P will take s2 across, then return by himself: M,d1,d2,F,s1,s2 | P,t

 

For the ninth and final trip, P will take t across.

 

This is assuming the thief can also be left unsupervised. The rules don't say otherwise (I guess the policeman can cuff him to a tree or something).

 

Edited by John
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departure Return

1- T+P P

2- P+S1 T+P

3- F+S2 F

4- F+M M

5- T+P F

6- M+F M

7- M +D1 T+P

8- P+D2 P

9- T+F

 

Hope that's it

 

Almost. Your last two trips violate the rule about the thief being with a family member without the policeman.

 

Edit: Actually, you're right, except on the last trip F shouldn't be with T, as F is already across the river. I think you made a typo and meant T+P. :)

Edited by John
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There are 8 people (Father, Mother, Thief, Policeman, 2 Sons, 2 Daughters) trying to cross a river by using a raft. Only the adults (excluding the thief) know how to operate the raft. A total of only 2 people are allowed on the raft at any given moment. The raft must travel back and forth across the river in order to pick up all of the people.

 

Rules:

You have the following people trying to cross a river:

 

Father

The father cannot stay with any of the daughters, without their Mother's presence.

Mother

The Mother cannot stay with any of the sons, without their Father's presence.

Thief

The thief cannot stay with any family member, if the policeman is not there.

Policeman

Allowed to travel with everyone.

2 Sons, 2 Daughters

Not allowed to travel without an adult, or be in the presence of the thief without the policeman's supervision. The sons are not allowed to be in the presence of their mother without the supervision of their father. The daughters are not allowed to be in the presence of their father without the supervision of their mother. Both the sons and daughters are allowed to be unsupervised (so long as all other rules are still satisfied).

 

In what sequence must everyone travel in order to get everyone to the other side of the river safely? (Keep in mind that the rules apply at ALL times, and not just on the raft.)

 

LOL some body needs to swim was my first thought but, now I see the possibility.

 

going= P and T, hallway there the thief jumps off, and drowns leading to a solution LOL no that's not it.

 

Police man tied Thief by a rope to the raft lol, nope.

 

LOL tie a rope to the raft and pull the boat back empty heheh maybe?

 

M + D first trip.

D goes back

D still in raft

 

Bonkers...

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