Merry Christmas from The German Mathematical Society

[GT49er]

Four: Waldemar leaves with three elves and four days food each. At the end of the first day, two return having eaten one day’s supply and keeping one for the return journey. Therefore between them they hand over four days food -two each for Waldemar and his accomplice. So for the remaining five days they have two days food plus the three they already have in stock.

No. That would leave W. and his chum with 5 days' worth to carry - three they already had, plus the two they were given. They can only carry four..

 

[KingKev]

Four.

 

[GT49er]

Four: Waldemar leaves with three elves and four days food each. At the end of the first day, two return having eaten one day’s supply and keeping one for the return journey. Therefore between them they hand over four days food -two each for Waldemar and his accomplice. So for the remaining five days they have two days food plus the three they already have in stock.

2 plus 3 = 5. They can only carry four!

 

[KingKev]

Four.

IE Waldemar plus 4.
After day 1 elves A and B return home with 3 days' worth of food between them; the others carry on and have 4 days each left; After day 2, C and D return home with 5 days' worth of food (they only need 4). Waldemar still has 4 days' worth of food and 4 days to go on the trip; job's a good'un.

 

[GT49er]

IE Waldemar plus 4.
After day 1 elves A and B return home with 3 days' worth of food between them; the others carry on and have 4 days each left; After day 2, C and D return home with 5 days' worth of food (they only need 4). Waldemar still has 4 days' worth of food and 4 days to go on the trip; job's a good'un.

You're not in the business of pricing up jobs and making a profit, I presume?

 

[Herr Tubthumper]

Do you want the answer?

 

[GT49er]

Do you want the answer?

Only if all 27(?) countries agree to it!

 

[Herr Tubthumper]

Only if all 27(?) countries agree to it!

26 all agreed but one vetoed it.

The answer is two elves.
Waldemar cannot complete the trip on his own, because he will run out of food after four days. So he needs to take at least one companion to carry the extra food.
Let’s say he takes his best friend, Edeltraud. Both elves start off with four days of food supplies. At the end of the first day, the elves have three days of supplies left each.
Now let Edeltraud give Waldemar a day’s supply of food, so Waldemar has four days worth, the maximum he can carry. This means that Edeltraud only has two days worth left.
At the end of the second day, Waldemar will have three days of food left, and Edeltraud has a single day of food. ELF DISASTER ALERT! Waldemar does not have enough food to complete the six day trip, and Edeltraud only has a single day of food left so she must return home or remain stranded in the desert with no food.
So, Waldemar must take at least two companions. Let’s say he takes Edeltraud and Johannes. They all leave Timbuktu with four days of food each.
At the end of the first day, they all have three days of food left. At this point Johannes gives one day of food to Waldemar and one to Edeltraud, leaving Johannes with only one day of food left and his companions with four each. Johannes then returns home.
At the end of the second day, Waldemar and Edeltraud are down to three days of food each. Edeltraud gives one day of food to Waldemar, meaning he has four days worth of food, enough to finish the trip since he has only four days left to go. Edeltraud, down to two days of food, also has enough food to return home and not be stranded.
So, the trip is possible with Waldemar plus two elves.
In fact, there is an alternative solution. Waldemar starts off with only Edeltraud, who gives him one day of food as above, leaving him with three days of food left at the end of day two. Waldemar has enough food for five days - but on the sixth day he meets Johannes, who has travelled out from Timbuktu and is waiting for him with his daily ration of food.

 

[perseus]

Four: Waldemar leaves with three elves and four days food each. At the end of the first day, two return having eaten one day’s supply and keeping one for the return journey. Therefore between them they hand over four days food -two each for Waldemar and his accomplice. So for the remaining five days they have two days food plus the three they already have in stock.

3 (1+2)
W used 1 (3+1) used 1 (2+2=4) = 6
B used 1 (3+1) used 1 (4-2) 2 to return
C used 1 (4-2) 1 to return

 

[Tom Hark Preston Park]

One additional elf. 8 days food between the two of them. Kill recruited elf and steal his food. job done.

This. The task could be completed using stollen cake.

 

[GT49er]

26 all agreed but one vetoed it.

The answer is two elves.
Waldemar cannot complete the trip on his own, because he will run out of food after four days. So he needs to take at least one companion to carry the extra food.
Let’s say he takes his best friend, Edeltraud. Both elves start off with four days of food supplies. At the end of the first day, the elves have three days of supplies left each.
Now let Edeltraud give Waldemar a day’s supply of food, so Waldemar has four days worth, the maximum he can carry. This means that Edeltraud only has two days worth left.
At the end of the second day, Waldemar will have three days of food left, and Edeltraud has a single day of food. ELF DISASTER ALERT! Waldemar does not have enough food to complete the six day trip, and Edeltraud only has a single day of food left so she must return home or remain stranded in the desert with no food.
So, Waldemar must take at least two companions. Let’s say he takes Edeltraud and Johannes. They all leave Timbuktu with four days of food each.
At the end of the first day, they all have three days of food left. At this point Johannes gives one day of food to Waldemar and one to Edeltraud, leaving Johannes with only one day of food left and his companions with four each. Johannes then returns home.
At the end of the second day, Waldemar and Edeltraud are down to three days of food each. Edeltraud gives one day of food to Waldemar, meaning he has four days worth of food, enough to finish the trip since he has only four days left to go. Edeltraud, down to two days of food, also has enough food to return home and not be stranded.
So, the trip is possible with Waldemar plus two elves.
In fact, there is an alternative solution. Waldemar starts off with only Edeltraud, who gives him one day of food as above, leaving him with three days of food left at the end of day two. Waldemar has enough food for five days - but on the sixth day he meets Johannes, who has travelled out from Timbuktu and is waiting for him with his daily ration of food.

Hold it a minute HT!

Clarifications: Waldemar can only travel with other elves.

Thus the assumption that W. cannot travel alone. In your solution, he's on his tod for several days. I rest my case!

 

[Herr Tubthumper]

Hold it a minute HT!



Thus the assumption that W. cannot travel alone. In your solution, he's on his tod for several days. I rest my case!

The clarification states elves can only travel with other elves. "Can" being the operative word here. It doesn't state elves must travel with other elves.

 

[Herr Tubthumper]

if Germany is that good--- stay there

Look at all the fun we are having with this puzzle. Do you not feel you have missed out?

 

[Superphil]

None, there's no such thing as Elves.

 

[Herr Tubthumper]

None, there's no such thing as Elves.

I refer you to post #13

 

[GT49er]

The clarification states elves can only travel with other elves. "Can" being the operative word here. It doesn't state elves must travel with other elves.

No, the key word is 'only' - if they can only travel with other elves, then by definition they cannot travel without other elves. Bloody EU regulations, I expect!

 

[Herr Tubthumper]

No, the key word is 'only' - if they can only travel with other elves, then by definition they cannot travel without other elves. Bloody EU regulations, I expect!

They're in Timbuktu so EU regulations don't apply here. That said, it might be useful to familiarise yourself with this place as a major trading partner alongside Peru and Albania once Brexit is finalised.

 

[Tom Hark Preston Park]

None, there's no such thing as Elves.

Bit premature shirley? He's not leaving on a free transfer til January.

 

[GT49er]

They're in Timbuktu so EU regulations don't apply here. That said, it might be useful to familiarise yourself with this place as a major trading partner alongside Peru and Albania once Brexit is finalised.

Obviously a problem in the translation from German to English then, leading to a critical misunderstanding. Just as well a common defence force and greater political unity are dead in the water, eh? Never mind, as Timbuktu isn't a nation anyway I doubt we'll be doing any trade partnership deals there.............

 

[Herr Tubthumper]

Obviously a problem in the translation from German to English then, leading to a critical misunderstanding. Just as well a common defence force and greater political unity are dead in the water, eh? Never mind, as Timbuktu isn't a nation anyway I doubt we'll be doing any trade partnership deals there.............

Not yet, but Mali recently and stupidly voted to leave the African Nations. As Timbuktu didn't want to be dragged into the economic abyss they, led by a fearsome and smart lady called Nicola Bambatta, sensibly had a second referendum and rejoined the AN as a separate nation.