PUZZLE (don't try it if you cry a lot)

[VBboy]

(Please do NOT try to solve this puzzle if you tend to cry a lot when you fail and are likely to get fired after a wasted day at work ).

There are four people who need to cross a bridge at night.
The bridge is only wide enough for two people to cross at once (only two people can use it at any given time). There is only one flashlight for the entire group. When two people cross, they must cross at the slower member's speed. All four people must cross the bridge in 17 minutes, since the bridge will collapse in exactly that amount of time. Here are the times each member takes to cross the bridge:

Person A: 1 minute
Person B: 2 minutes
Person C: 5 minutes
Person D: 10 minutes

So, if Person A and C crossed the bridge initally, 5 minutes would elapse, because Person C takes 5 minutes to cross. Then, Person A would have to come back to the other side of the bridge, taking another minue, or six minutes total. Now, if Person A and D crossed the bridge next, it would take them 10 minutes, totalling to 16 minutes. If A came back, it would take yet another minute, totally 17... the bridge would collapse with A and B on the wrong side. How can all four people get across the bridge within 17 minutes?

Note: there is no trick-answer to this problem. You can't do tricky stuff like throwing the flashlight back from one end of the bridge to the other. This problem can be solved.

P.S. If this is a repost, I apologize.

<Below are a few blank lines so that if someone solves it, you don't automatically see that post>

 

[Electrode]

Why can't all 4 go at once? The width of the bridge is meaningless if they don't all walk side-by-side...

 

[VBboy]

Originally posted by: Electrode
Why can't all 4 go at once? The width of the bridge is meaningless if they don't all walk side-by-side...

Sorry, no-go with that idea These are the rules. 2 people at once.

 

They are all blind, therefor they do not need flashlights, they cross in two groups.

 

[Rkonster]

A and B go over. Making that 2 minutes.
A goes back. Making that 3 minues.
C and D go over. Making that 13 minutes.
B goes back. Making that 15 minutes.
A and B go over. Making that 17 minutes.

 

[Orsorum]

Originally posted by: Rkonster
A and B go over. Making that 2 minutes.
A goes back. Making that 3 minues.
C and D go over. Making that 13 minutes.
B goes back. Making that 15 minutes.
A and B go over. Making that 17 minutes.

What he said.

 

[iamwiz82]

there is a flash version of this out there

 

[VBboy]

Originally posted by: Zakath15

Originally posted by: Rkonster
A and B go over. Making that 2 minutes.
A goes back. Making that 3 minues.
C and D go over. Making that 13 minutes.
B goes back. Making that 15 minutes.
A and B go over. Making that 17 minutes.

What he said.

That's interesting.
How did you know he said it, unless you scrolled down? And if you solved it and scrolled down to answer it, why not just post it in your wn words?

 

[Orsorum]

Originally posted by: VBboy

Originally posted by: Zakath15

Originally posted by: Rkonster
A and B go over. Making that 2 minutes.
A goes back. Making that 3 minues.
C and D go over. Making that 13 minutes.
B goes back. Making that 15 minutes.
A and B go over. Making that 17 minutes.

What he said.

That's interesting.
How did you know he said it, unless you scrolled down? And if you solved it and scrolled down to answer it, why not just post it in your wn words?

I solved it in my head.

 

[VBboy]

Originally posted by: Zakath15

Originally posted by: VBboy

Originally posted by: Zakath15

Originally posted by: Rkonster
A and B go over. Making that 2 minutes.
A goes back. Making that 3 minues.
C and D go over. Making that 13 minutes.
B goes back. Making that 15 minutes.
A and B go over. Making that 17 minutes.

What he said.

That's interesting.
How did you know he said it, unless you scrolled down? And if you solved it and scrolled down to answer it, why not just post it in your wn words?

I solved it in my head.

Are all lifers such big cheaters?
j/k. Some people are just more gifted than others

 

[Qacer]

You never mentioned their height. Assuming all four participants are midgets, then two midgets will carry the other two on their shoulders. Two midgets equal one normal size person. So, the answer is 2^2. With two midgets carrying midgets on their shoulders, they would cross the bridge together and still fulfill the requirements that only two people are allowed to cross the bridge because two midgets equal one normal size person.

 

[VBboy]

Originally posted by: Qacer
You never mentioned their height. Assuming all four participants are midgets, then two midgets will carry the other two on their shoulders. Two midgets equal one normal size person. So, the answer is 2^2. With two midgets carrying midgets on their shoulders, they would cross the bridge together and still fulfill the requirements that only two people are allowed to cross the bridge because two midgets equal one normal size person.

What is this obsession with midgets that you people have!
I bet you answer all your exam questions in midget terms.

 

[Feanor727]

This problem was much cooler when it was Larry, Adam, The Edge and Bono instead of Person A, B, C, D...