rookie1ja Posted March 31, 2007 Report Share Posted March 31, 2007 Humans and Monkeys - Back to the River Crossing Puzzles Three humans, one big monkey and two small monkeys are to cross a river: * Only humans and the big monkey can row the boat. * At all times, the number of humans on either side of the river must be greater or equal to the number of monkeys on that side. (Or else the humans will be eaten by the monkeys!) * The boat only has room for 2 (monkeys or humans). * Monkeys can jump out of the boat when it's banked. This old topic is locked since it was answered many times. You can check solution in the Spoiler below. Pls visit New Puzzles section to see always fresh brain teasers. Humans and Monkeys - solution The three columns represent the left bank, the boat, and the right bank respectively. The < or > indicates the direction of motion of the boat. HHHMmm . . HHHm Mm> . HHHm <M m HHH Mm> m HHH <M mm HM HH> mm HM <Hm Hm Hm HM> Hm Hm <Hm HM mm HH> HM mm <M HHH m Mm> HHH m <M HHHm . Mm> HHHm . . HHHMmm Link to comment Share on other sites More sharing options...
Guest Posted May 4, 2007 Report Share Posted May 4, 2007 HUH!?!? Link to comment Share on other sites More sharing options...
Guest Posted May 4, 2007 Report Share Posted May 4, 2007 HUH!?!? in english please! Link to comment Share on other sites More sharing options...
rookie1ja Posted May 4, 2007 Author Report Share Posted May 4, 2007 HUH!?!? in english please! . is an empty bank (or an empty boat in the first and the last step) H is a human M is a big monkey m is a small monkey > is going right Link to comment Share on other sites More sharing options...
Guest Posted May 26, 2007 Report Share Posted May 26, 2007 ok, nevermind, I didn't understand the monkeys jump out when it banks at first.... Link to comment Share on other sites More sharing options...
Guest Posted June 27, 2007 Report Share Posted June 27, 2007 ADMIN this is yours 15 steps (and this is mine 12 steps) The three columns represent the left bank, the boat, and the right bank respectively. The < or > indicates the direction of motion of the boat. HHHMmm . . (HHHMmm . .) HHHm Mm> . (HHHm Mm> .) HHHm HHH Mm> m (HHH Mm> m) HHH HM HH> mm (HM HH> mm) HM Hm HM> Hm --------- Hm Hm) mm HH> HM (Mm mm HHm) m Mm> HHH (M m HHHMmm) . Mm> HHHm . . HHHMmm Link to comment Share on other sites More sharing options...
Guest Posted July 2, 2007 Report Share Posted July 2, 2007 ADMIN this is yours 15 steps (and this is mine 12 steps) The three columns represent the left bank, the boat, and the right bank respectively. The < or > indicates the direction of motion of the boat. HHHMmm . . (HHHMmm . .) HHHm Mm> . (HHHm Mm> .) HHHm HHH Mm> m (HHH Mm> m) HHH HM HH> mm (HM HH> mm) HM Hm HM> Hm --------- Hm Hm) mm HH> HM (Mm mm HHm) m Mm> HHH (M m HHHMmm) . Mm> HHHm . . HHHMmm Link to comment Share on other sites More sharing options...
Guest Posted July 16, 2007 Report Share Posted July 16, 2007 if the number of humans is zero on one side but there are multiple monkeys does it matter? (after all, the humans cannot be eaten if they are not there) Link to comment Share on other sites More sharing options...
Guest Posted July 16, 2007 Report Share Posted July 16, 2007 how about this:- HHHMmm... HHMm >Hm... HHMm...Hm HM >Hm...Hm HM...HHmm >HM...HHmm ...HHHMmm sounds rite ??? Link to comment Share on other sites More sharing options...
Guest Posted July 19, 2007 Report Share Posted July 19, 2007 HHH, Mmm HH mm HM> ........ HH mm <M H HH m Mm> H HH m <H Mm HH Hm> Mm HH <H Mmm H HH> Mmm H <M HH mm ........ HM> HHH Mmm ........ ...... HHH Mmm Isn't this right Link to comment Share on other sites More sharing options...
Guest Posted July 20, 2007 Report Share Posted July 20, 2007 Actually, if you properly adhere to the puzzle requirements there is no apparent solution. Even the admin's solution violates the requirement "At all times, the number of humans on either side of the river must be greater or equal to the number of monkeys on that side". At any time, any side having only monkeys violates this rule since 0 Humans is not greater or equal to 1, 2 or 3 monkeys. For the admin solution to be correct, the requirement would need to be revised to state "At all times, the number of humans must be greater or equal to the number of monkeys on any side of the river having both monkeys and humans". HHHMmm . . HHHm Mm> . <<< Right Side has 2 Monkeys and 0 Humans HHHm HHH Mm> m <<< Right Side has 3 Monkeys and 0 Humans (once banked) HHH HM HH> mm HM Hm HM> Hm Hm mm HH> HM <<< Left Side has 2 Monkeys and 0 Humans mm m Mm> HHH <<< Left Side has 1 Monkey and 0 Humans m . Mm> HHHm . . HHHMmm Some would say having only monkeys on a given side would not result in a human being eaten by monkeys. That may sound reasonable, but the rule still exists that # Humans >= Monkeys "At all times ... on either side". Chris Link to comment Share on other sites More sharing options...
Guest Posted July 26, 2007 Report Share Posted July 26, 2007 Big Monkey always rows the boat. First take a human, then a monkey, then Human, then monkey, then human. HHHmmM --------- HHmm MH > HHmm HHm Mm > H HHm < M Hm Hm MH > Hm Hm < M HHm H Mm > HHm H < M HHmm MH > HHmm HHHMmm There are always the same or more humans on each side. However, BIG MONKEY worked up an appetite taking everyone across the river and ate all the humans and the monkeys. Haven't you seen King Kong? OOGA BOOGA Link to comment Share on other sites More sharing options...
Guest Posted July 28, 2007 Report Share Posted July 28, 2007 Big Monkey always rows the boat. First take a human, then a monkey, then Human, then monkey, then human. HHHmmM --------- HHmm MH > HHmm HHm Mm > H <--- There are 3 monkeys and 2 humans before the boat sets out. HHm < M Hm Hm MH > Hm Hm < M HHm H Mm > HHm H < M HHmm <--- There are 3 monkeys and 2 humans before the boat sets out. MH > HHmm HHHMmm There are always the same or more humans on each side. However, BIG MONKEY worked up an appetite taking everyone across the river and ate all the humans and the monkeys. Haven't you seen King Kong? OOGA BOOGA Link to comment Share on other sites More sharing options...
Guest Posted August 2, 2007 Report Share Posted August 2, 2007 have the big monkey go back and forth in the boat, and ferry every1 over 1 by one when alternating starting with a human Link to comment Share on other sites More sharing options...
Guest Posted October 1, 2007 Report Share Posted October 1, 2007 "Ankur" Remember that some one has to send the boat back Link to comment Share on other sites More sharing options...
Guest Posted November 3, 2007 Report Share Posted November 3, 2007 O=big monkey m=little monkey X=human >=across the bank <=back from across the bank XX> X< XX> X< Xm> X< Xm> X< XO> im the best in the world Link to comment Share on other sites More sharing options...
Guest Posted November 22, 2007 Report Share Posted November 22, 2007 O=big monkey m=little monkey X=human >=across the bank <=back from across the bank XX> X< XX> X< Xm> X< Xm> X< XO> im the best in the world In your very first line, you have already left 1 human (X) behind with all of the monkeys (m & O). You have to consider the number of monkeys and humans on both sides. Link to comment Share on other sites More sharing options...
Guest Posted November 30, 2007 Report Share Posted November 30, 2007 I don't see how any of these solutions work due to this line: * At all times, the number of humans on either side of the river must be greater or equal to the number of monkeys on that side. (Or else the humans will be eaten by the monkeys!) If it clarified that it's okay for a monkey to be alone I could understand, but it doesn't clarify that. It says AT ALL TIMES - GREATER OR EQUAL TO. Basically that's a trap. If this were true this would be impossible to solve. This is not a smart or good puzzle in my opinion. Link to comment Share on other sites More sharing options...
Guest Posted December 2, 2007 Report Share Posted December 2, 2007 Humans and Monkeys... his is wrong because a man and a small monkey CANNOT! ride together, though ilogical that a big monkey is less threating or is easy to go across a river with than a small monkey it is the rule. no my way seem to be way easier and follows the rules HHHMmm . . HHHMmm. . HHHm Mm>. HHmm HM>.. HHHm <M m HHmm <M H HHH Mm> m HHm Mm> H HHH <M mm HHm <M Hm HM HH> mm Hm MH> HHm HM <Hm Hm Hm <M HHm Hm HM> Hm m HM> HHm Hm <Hm HM m <M HHHm mm HH> HM .. mM> HHHm mm <M HHH ... HHHMmm m Mm> HHH m <M HHHm . Mm> HHHm ..HHHMmm try to correct because i see no flaw <!-- s8) --><!-- s8) --> Link to comment Share on other sites More sharing options...
rookie1ja Posted December 2, 2007 Author Report Share Posted December 2, 2007 Humans and Monkeys... his is wrong because a man and a small monkey CANNOT! ride together, though ilogical that a big monkey is less threating or is easy to go across a river with than a small monkey it is the rule. no my way seem to be way easier and follows the rules HHHMmm . . HHHMmm. . HHHm Mm>. HHmm HM>.. HHHm <M m HHmm <M H HHH Mm> m HHm Mm> H HHH <M mm HHm <M Hm HM HH> mm Hm MH> HHm HM <Hm Hm Hm <M HHm Hm HM> Hm m HM> HHm Hm <Hm HM m <M HHHm mm HH> HM .. mM> HHHm mm <M HHH ... HHHMmm m Mm> HHH m <M HHHm . Mm> HHHm ..HHHMmm try to correct because i see no flaw <!-- s8) --><!-- s8) --> I am right because a human and a small monkey CAN! ride together ... where does it say the opposite? Link to comment Share on other sites More sharing options...
Guest Posted December 29, 2007 Report Share Posted December 29, 2007 I think that one big monkey, two small monkeys, and two humans initially approach a boat when they initiate this endeavor. Wouldn't that immediately put a stop to this problem since, before any thing gets on the boat the first time we're already dealing with a situation where we have 3 monkeys and 2 humans? Link to comment Share on other sites More sharing options...
Guest Posted January 4, 2008 Report Share Posted January 4, 2008 Another solution that requires the same 13 crossings is: HHHMmm... HHMm Hm> HHMm HHH Mm> m HHH HM HH> mm HM Hm HM> Hm Hm mm HH> HM mm m Mm> HHH m mM> mHHH ...mmMHHH Link to comment Share on other sites More sharing options...
Guest Posted January 9, 2008 Report Share Posted January 9, 2008 (edited) Only big monkey and humans can row the boat and # of human has to be >= # of monkeys HHHMmm HHHm --> Mm HHHm <-- M m HHm --> MH m HHm <-- M Hm <----- being eaten Hm --> MH Hm Hm <-- M HHm <----- being eaten H --> Mm HHm <----- being eaten H <-- M HHmm --> MH HHmm HHHMmm I totally forgot the the last point where the monkey can jump out of the boat. So it will have to be revised according to the solution. Edited January 9, 2008 by biodreamer Link to comment Share on other sites More sharing options...
Guest Posted January 29, 2008 Report Share Posted January 29, 2008 what with all the h's and m's and >'s and <'s and .'s i just have one thing to say: Hmmmmm>Hmmmmm<Hmmmm....??? Link to comment Share on other sites More sharing options...
Guest Posted February 14, 2008 Report Share Posted February 14, 2008 how about this:- HHHMmm... HHMm >Hm... HHMm...Hm HM >Hm...Hm <---who will bring back the boat HM...HHmm >HM...HHmm ...HHHMmm sounds rite ??? Link to comment Share on other sites More sharing options...
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