[rookie1ja]

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?

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.

Spoiler for old wording:

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?

[colorclown26]

hm......

[Measure]

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.

[oneandonlyJosh]

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

[moboo's pain]

or they can just go single file through the tunnel and wat kind of tunnel can only have two people abroad?

[Wolken]

through the tight tunnel can go at once not more than two persons moving....

WTF? I dont think that makes any sense.

[apa]

Apparently the tunnel has a weak bridge going through the entire thing.

[tfitz11]

if its dark outside they're all hosed.

[spunkalicious]

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...

[KBHoleN1]

Quote

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.