Can anyone solve this riddle?

B

brandons1313

It Wandered In From the Wastes
There are 4 women who want to cross a bridge. They all begin on the same side. You have 17 minutes to get all of them across to the other side. It is night. There is one flashlight. A maximum of two people can cross at one time. Any party who crosses, either 1 or 2 people, must have the flashlight with them. The flashlight must be walked back and forth, it cannot be thrown, etc. Each woman walks at a different speed. A pair must walk together at the rate of the slower woman's pace.

Woman 1: 1 minute to cross
Woman 2: 2 minutes to cross
Woman 3: 5 minutes to cross
Woman 4: 10 minutes to cross

For example if Woman 1 and Woman 4 walk across first, 10 minutes have elapsed when they get to the other side of the bridge. If Woman 4 then returns with the flashlight, a total of 20 minutes have passed and you have failed the mission. What is the order required to get all women across in 17 minutes? Now, what's the other way?
 
SPOILER!

mark to read

women 1 and 2 cross the bridge -> 2 min.
woman 1 walks back with flashlight -> 1 min.
women 3 and 4 cross the bridge -> 10 min.
woman 2 walks back with flashlight -> 2 min.
women 1 and 2 cross the bridge -> 2 min.

total: 17 minutes

only works if nobody breaks the flashlight

/SPOILER

Old and quite easy. Roland the Gunslingers would have laughed.
 
Group 1:
woman 1
woman 2
2 minutes pass to get to the end


woman 1 returns
1 minutes passes to return to start

Group 2:
woman 3
woman 4
10 minutes pass to get to the end


woman 2 returns
2 minutes pass to return to start

Group 3:
woman 1
woman 2
2 minutes pass to get to the end

17 minutes in total.


This seems right and hopefully I explained it clearly. I am sitting in my room with a high fever and massive headache, however, so I hope I am not making a fool of myself.

:D

EDIT: Damn, too late in answering. Shouldn't have left the room for so long. :(
 
I thought outside the box, erroneously probabaly, and believed that the solution lay in them not having to remain on the other side of the bridge, but only 'visit' it. One can do this is many ways:

Group 1: 4,1. (10min)
1 returns (11min)
Group 2: 2,3 (16min)

1 is left on starting side, but has touched opposite bank. Thus, all four women have crossed the bridge satisfying the criteria.
 
good job. You beat me to it.

How about this one...

You've got someone working for you for seven days and a gold bar to pay them. The gold bar is segmented into seven connected pieces. You must give them a piece of gold at the end of every day. If you are only allowed to make two breaks in the gold bar, how do you pay your worker?
 
Once again, I'd say "get him to break the pieces off" but I think that defeats the object somewhat.
 
Easy. The first day you break the gold into two pieces, one of 6 and one of 1. You give the one gold bar, retaining 6 yourself.
The next day you break off a piece of 2. This makes for a piece of 2, a piece 4 and a piece of 1. You ask for the piece of 1 back and give him the piece of 2. The day after that you give him the piece of 2 as well.
The day after that you ask for the two pieces back and give him the piece of four.
The day after that you give him the piece of one as well.
The day after you ask him for the piece of one back and give him the piece of two.
The day after that you give him the piece of 1 as well. Ta-da.
This gives you the following scheme:
Worker - You
1-6
2-(4-1)
(2-1)-4
4-(2-1)
(4-1)-2
(4-2)-1
(4-2-1)-0
 
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