M*A*S*H

[koal]

Imagine four soldiers on their way to the hospital. They all are hurt more or less seriously. It is dark and they arrive at a bridge leading across a very wide river. The bridge doesn’t look very reliable and it’s obvious that it bears a maximum of two men at a time. The bridge itself should be rather called a “skeleton” than a “bridge” because it has many holes, gaps and traps. That’s why the soldiers have to carry a torch with them. Their first problem is the number of torches they have. It is 1 ! The second problem is the time, the torch will give light. The third problem is the different grade of injury of each soldier. Let’s call them S1, S2, S5 and S10. S1 will cross the bridge within a minute. S2 will need twice as long, whereas S5 and S10 need 5 and 10 Minutes respectively.

If all soldiers reach the other side of the river, what’s the minimum time, the torch has to give light?

o There is no way to throw the torch
o They have no tools except the torch and a zippo
o The zippo falls into the river a soon as the torch is lit ;)

[Kevin]

PM'd my solution. Now for some alternative problems.....

There's a traveler with a wolf, a goat, and a cabbage, and he needs to cross a river. The traveler can only carry one of his items at a time, and he can't leave the goat alone with the cabbage, or the wolf alone with the goat. How does he ferry all his wares across the river?

There are 3 brides and 3 husbands who need to cross a river. The boat holds at most 2 people. Because of jealousy, no woman may be left with another man unless her husband is present. How do they do it?

Three missionaries and 3 cannibals want to cross a river. The boat holds at most 2 people. The cannibals may never outnumber the missionaries. How do they ferry everyone across?

Three soldiers wish to cross a river. Two boys with a boat come to help them. The boat can only hold up 2 boys or 1 soldier. How do they get everyone across?

[Wacky]

Well, I don't see where you say that they must carry a lighted torch.

So my solution is to never light the torch at all. Just carry it with the person crossing the bridge. Use the zippo for light, if needed.

But I suspect that you will "clarify" the restrictions ....

[koal]

:D as I said: ... many holes, gaps and traps ... They need light ... either the zippo or the torch which - if lit - causes the zippo to get lost!

8)

[trif]

Are we losing posts, because we seem to be getting puzzles we've had before, but I can't find the old posts.

[koal]

:) Okay - someone told me, that the zippo would be enough to yield as an illuminating tool. So let's redefine the question: what's the minimum time the four soldiers can cross the river with only one tool for giving light? The number of minutes is - what else - prime!

8) koal

[Fusion_power]

19 minutes

[hyh1048576]

Originally Posted by Fusion_power

19 minutes

No!It should be 17 minutes ;)

17=2+2+10+1+2

[S80780]

I'd also say 19 minutes.
It is obvious that S1 is always one of the two soldiers, as he is the fastest.
So the minimum time spend is

10 (S1 and S10 cross the river)
+1 (S1 returns)
+5 (S1 and S5 cross the river)
+1 (S1 returns)
+2 (S1 and S2 cross the river)
----
19 minutes

Benjamin

[hyh1048576]

Originally Posted by S80780

I'd also say 19 minutes.
It is obvious that S1 is always one of the two soldiers, as he is the fastest.
So the minimum time spend is

10 (S1 and S10 cross the river)
+1 (S1 returns)
+5 (S1 and S5 cross the river)
+1 (S1 returns)
+2 (S1 and S2 cross the river)
----
19 minutes

Benjamin

Too Bad!!!!!It is obvious that S1 is always one of the two soldiers :? Not obvious!!!

2 (S1 and S2 cross the river)
2 (S2 returns)
10 (S10 and S5 cross the river)
1 (S1 returns)
2 (S1 and S2 cross the river)

DING!!!!!17MINUTES