38 replies to this topic

[postbost]

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

[sunshipballoons]

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.

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

[mollie]

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...

[DoubleT]

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

[hardxkorEMF]

[quote name='rookie1ja' date='Mar 31 2007, 12:12 PM' post='126']
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.

[/quote


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

[my massive brain is sexy]

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

[mswelldone]

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.

[mswelldone]

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?

[rainbow-]

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