38 replies to this topic

[Yugi]

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)

[Yugi]

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 by Yugi, 15 March 2008 - 04:24 PM.

[Jno1213]

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?

[mindlessloner]

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

[ash013]

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

[brainwwings]

How can a tunnel accomodate only 2 people at a time? A tunnel is a long passageway - no matter how tight or close, it can accomodate a steady flow of any # of people. And like most passageways, be it hiking trails, hallways or stairwells, they are navigated single-file. With the daughter at the head of the line and the father bringing up the rear holding the torch as high as possible in front of him, he'd provide enough light for the other to navigate comfortably through the tunnel in, what was the maximum time, 5 min? and have more than enough battery power left for a round trip.

Who would navigate through an unlighted tunnel, anyway? And having to without a light source would make anybody apprehensive.

[lulu1221]

mom + dad = 2
mom comes back = 4
daughter + son = 9
dad comes back = 10
mom + dad = 12

[atulchaudhary]

Dark 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, 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?

Spoiler for Solution

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.

The combination would be -
1+2= 2 min
1 goes back= 3 min in total
5+4= 5 min (8min in total)
then 2 goes back=2min (10 min in total)
1+2=2 min (12 min in total)

It is really an easy one !!!

[L.L.]

Yes!
Mom & Dad go first (because the adults should go first just to make sure it is safe) 2 min
Dad comes back to bring the light to the kids (Dads are good at reassuring them) 1 min
Brother & Sister go across 5 min
Mom brings the light back across to dad (Men always need women to fetch them items) 2 min
Mom and Dad come back across 2 min
2+1+5+2+2= 12 minutes!!

[Alchameth]

Here is my question....

Dad can make it through in one minute so that leaves 2 possibilities. Either the tunnel is not that long or he is "The Flash ™"

Now they are all afraid of the dark, so either it is light out and no need for the torch because the tunnel is so short and the light would travel through it making it not that dark leaving no need for the torch, or it is dark outside and hopefully it is a train tunnel and mom and dad get run over for leaving their kids who are terrified of the dark on the far side of the tunnel without a torch and alone. Because the fact that the daughter takes 5 minutes and son 4 implies that they are either young or disabled in some fashon; either way call CPS and lock those parents up, and why for the love of god are they out there in the first place?

Either way something is amuk!