BrainDen.com - Brain Teasers

# Dark Phobia

## 39 posts in this topic

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.

##### Share on other sites

mom comes back = 4

daughter + son = 9

##### Share on other sites
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?

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 !!!

##### Share on other sites

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!!

##### Share on other sites

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!

##### Share on other sites

I belie believe you need to state that the torch must be carried back through the tunnel each time

##### Share on other sites
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?

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.

It also works to switch mom's and dad's roles.

##### Share on other sites

Wait, wait, wait... If they're afraid of the dark, wouldn't they get so scared that they run as fast as their 'fraidy cat legs will take them to the other side? Or, since you didn't say they needed to get through right away, couldn't they go to therapy first? Or take an airplane? And how did they get in this dilemma in the first place? At least with river crossing ones I can picture them as, like, illegal immigrants or something...

##### Share on other sites

It can't be done:

1 & 2 go --- 2 minutes

1 comes back --- 3 minutes

1 & 4 go --- 7 minutes

1 comes back --- 8 minutes

1 & 5 go --- 13 minutes

In the quickest situation 1 and someone else will lose light with a minute left

##### Share on other sites

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?

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.

[/quote

if the longest time is the little girls wouldnt the torch only need to last 5 min

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

dude, thats what i said, and then it would only take 5mins =D

##### Share on other sites

Wow, is there some mathematical equation that can be used to figure that out? I had not considered wasting time by having the parents make the trip together.

##### Share on other sites
I belie believe you need to state that the torch must be carried back through the tunnel each time

How much fun would that be?

##### Share on other sites
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.

well if the family finds the solution before they light the torch, and begin after it's lit. Then it's not "game over, man" ahahaha

• 1