rookie1ja Posted March 31, 2007 Report Share Posted March 31, 2007 Darkness Phobia - Back to the River Crossing Puzzles One family wants to get through a tunnel. Dad can make it in 1 minute, mama in 2 minutes, son in 4 and daughter in 5 minutes. Unfortunately, not more than two persons can go through the narrow tunnel at one time, moving at the speed of the slower one. Can they all make it to the other side if they have a torch that lasts only 12 minutes and they are afraid of the dark? 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. Dark Phobia - solution First mom and dad – 2 minutes. Dad comes back – 3 minutes, both children go to mom – 8 minutes. Mom comes to dad – 10 minutes and they both get to their children – 12 minutes. One family wants to get through a tunnel. Dad can make it in 1 minute, mama in 2 minutes, son in 4 and daughter in 5 minutes. Unfortunately, through the tight tunnel can go at once not more than two persons moving at the speed of the slower one. Can they all make it if they have a torch that lasts only 12 minutes and they are afraid of the dark? Link to comment Share on other sites More sharing options...
Guest Posted June 28, 2007 Report Share Posted June 28, 2007 hm...... Link to comment Share on other sites More sharing options...
Guest Posted June 29, 2007 Report Share Posted June 29, 2007 Sure, they might be able to make it, but by the time they figure out the solution, they'll only have 7 minutes left on that torch. game over, man. Link to comment Share on other sites More sharing options...
Guest Posted July 9, 2007 Report Share Posted July 9, 2007 Of course, one can conquer one's fears. Just walk down the dark tunnel. 1 & 2 go 1 or 2 comes back 4 & 5 go 1 or 2 comes back (the one that didn't come back before) 1 & 2 go 2+1+5+2+2=12 minutes Link to comment Share on other sites More sharing options...
Guest Posted July 14, 2007 Report Share Posted July 14, 2007 or they can just go single file through the tunnel and wat kind of tunnel can only have two people abroad? Link to comment Share on other sites More sharing options...
Guest Posted July 17, 2007 Report Share Posted July 17, 2007 through the tight tunnel can go at once not more than two persons moving.... WTF? I dont think that makes any sense. Link to comment Share on other sites More sharing options...
Guest Posted July 18, 2007 Report Share Posted July 18, 2007 Apparently the tunnel has a weak bridge going through the entire thing. Link to comment Share on other sites More sharing options...
Guest Posted July 26, 2007 Report Share Posted July 26, 2007 if its dark outside they're all hosed. Link to comment Share on other sites More sharing options...
Guest Posted July 27, 2007 Report Share Posted July 27, 2007 I would think so because when you add up their times, 1 + 2 + 4 + 5 = 12...but that doesn't include thier going back and forth to hand off the torch, right? So no, it wouldn't really work, unless the torch could fly between them... Link to comment Share on other sites More sharing options...
Guest Posted August 28, 2007 Report Share Posted August 28, 2007 through the tight tunnel can go at once not more than two persons moving.... WTF? I dont think that makes any sense. It's sort of Old English, but it's grammatically correct. Think of it like this: through the tight tunnel, can go, at once, not more than two persons. Some pauses are required to get the meaning of the sentence. Link to comment Share on other sites More sharing options...
Guest Posted September 6, 2007 Report Share Posted September 6, 2007 I would think so because when you add up their times, 1 + 2 + 4 + 5 = 12...but that doesn't include thier going back and forth to hand off the torch, right? So no, it wouldn't really work, unless the torch could fly between them... you are wrong because say 4+5 went together...it didnt take 9 minutes it only took 5....the answer is that the fastest they could have done it in is 13 minutes so they fail... 1+5 went = 5 minutes 1 went back = 6 minutes 1+4 went = 10 minutes 1 went back = 11 minutes 1+2 went = 13 minutes the quickest way is ALWAYS going to be with 1 being the one going back...so therefore it is impossible Link to comment Share on other sites More sharing options...
Guest Posted September 18, 2007 Report Share Posted September 18, 2007 what of they went in a diamond pattern. 2 in front (the fastest), 1 in the middle (the brother, 4 minuets) and the sister behind the brother and the brother holds the torch high so that the light can be distributed over the runners. Link to comment Share on other sites More sharing options...
Guest Posted September 23, 2007 Report Share Posted September 23, 2007 I would think so because when you add up their times, 1 + 2 + 4 + 5 = 12...but that doesn't include thier going back and forth to hand off the torch, right? So no, it wouldn't really work, unless the torch could fly between them... you are wrong because say 4+5 went together...it didnt take 9 minutes it only took 5....the answer is that the fastest they could have done it in is 13 minutes so they fail... 1+5 went = 5 minutes 1 went back = 6 minutes 1+4 went = 10 minutes 1 went back = 11 minutes 1+2 went = 13 minutes the quickest way is ALWAYS going to be with 1 being the one going back...so therefore it is impossible they were right in saying they could successfully complete the trip in the twelve minutes. just because 1 minute is the lowest value doesnt mean its necessarily the most time conservative to have that person go back and forth each time. Link to comment Share on other sites More sharing options...
Guest Posted October 12, 2007 Report Share Posted October 12, 2007 first mama and papa go 2 minutes lost than papa came back 3 mins total cost daughter and son to meet the mom will spend another five total time is eight mom come back to meet dad alone time left is two minutes as 10 minutes are gone papa mama go together for final get together 2 minutes for themselv making the total 12 (horrible horrible poem) Link to comment Share on other sites More sharing options...
Guest Posted November 17, 2007 Report Share Posted November 17, 2007 i think the best way is always the hardest way.... Link to comment Share on other sites More sharing options...
Guest Posted November 20, 2007 Report Share Posted November 20, 2007 Ok im confused by the wording to the answer Link to comment Share on other sites More sharing options...
Guest Posted November 28, 2007 Report Share Posted November 28, 2007 ya they might make it but i dont think they would Link to comment Share on other sites More sharing options...
Guest Posted February 4, 2008 Report Share Posted February 4, 2008 dad= d mum= m son= s dauter= da m+d d comes back s+da m comes back m+d alltogether 12 if somebodys already answered this soz i didnt read all the enties Link to comment Share on other sites More sharing options...
Guest Posted February 25, 2008 Report Share Posted February 25, 2008 first mama and papa go 2 minutes lost than papa came back 3 mins total cost daughter and son to meet the mom will spend another five total time is eight mom come back to meet dad alone time left is two minutes as 10 minutes are gone papa mama go together for final get together 2 minutes for themselv making the total 12 (horrible horrible poem) if mom and dad are left alone, it could lead to some more loss of time, better be careful Link to comment Share on other sites More sharing options...
Guest Posted February 28, 2008 Report Share Posted February 28, 2008 It's sort of Old English, but it's grammatically correct. Think of it like this: through the tight tunnel, can go, at once, not more than two persons. Some pauses are required to get the meaning of the sentence. so the tunnel is just tight, meaning that only 2 can walk abreast. but why cant they walk in rows of two? there is nothing to suggest that they couldnt. of course im sure its much more complex than just that, but part of riddles is looking outside the box. if it were a flashlight, they could roll it back through the tunnel to the next set Link to comment Share on other sites More sharing options...
Guest Posted March 15, 2008 Report Share Posted March 15, 2008 I would think so because when you add up their times, 1 + 2 + 4 + 5 = 12...but that doesn't include thier going back and forth to hand off the torch, right? So no, it wouldn't really work, unless the torch could fly between them... I see what you mean, but I think your forgetting the fact that 2 people can go at once. (you can also work it out on paper to see) Link to comment Share on other sites More sharing options...
Guest Posted March 15, 2008 Report Share Posted March 15, 2008 (edited) The question says its a tight tunnel, so 2 people can go, but why cant they go in a four way square holding the torch in the middle so it gives light for everyone?It's a tunnel so length isn't even in the equasion Edited March 15, 2008 by Yugi Link to comment Share on other sites More sharing options...
Guest Posted March 21, 2008 Report Share Posted March 21, 2008 1 and 2 go = 2 mins 1 goes back = 1 min (3 mins total) 1 and 5 go = 5 mins (8 mins total) 1 goes back = 1 min (9 mins total) 1 and 4 go = 4 mins (12 mins total) OR...they can go four at a time, just 2 x2.......can't they? Link to comment Share on other sites More sharing options...
Guest Posted March 23, 2008 Report Share Posted March 23, 2008 1 and 2 go = 2 mins 1 goes back = 1 min (3 mins total) 1 and 5 go = 5 mins (8 mins total) 1 goes back = 1 min (9 mins total) 1 and 4 go = 4 mins (12 mins total) OR...they can go four at a time, just 2 x2.......can't they? 9+4 does not equal 12 Link to comment Share on other sites More sharing options...
Guest Posted March 25, 2008 Report Share Posted March 25, 2008 1 and 2 go(2min) 1 goes back(1min) 3 and 4 go(5min) 2 goes back(2min) 1 and 2 go(2min) 2+1+5+2+2=12 Link to comment Share on other sites More sharing options...
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