One for you Mathematicians...

[Dav0s]

Oops - wrote down the wrong thing! Corrected now.

Anyway, here's another riddle type thing (hopefully I won't make a mistake this time!)

A man has a set of scales and 40 bags of cement, weighing from 1kg to 40kg (i.e. a 1kg bag, 2kg bag, etc.). He places each bag on one side of the scales in turn. What is the minimum number of weights overall you need to balance out the scales each time?

For example, let's say you balance the 1kg bag with a 1kg weight. For the 11kg bag, you use a 1kg weight and a 10kg weight. So far, you have used 2 weights - 1kg and 10kg.

Does that make sense? Anyway, as I said, what is the minimum number of weights overall you need to balance out the scales each time? If do find the answer, don't spoil it!

YGPM

ive had a go.

[Scarlet Infidel]

Yawn, i think itd be fun to have Maths challenges on the bored, harder than this one though.

[herulach]

Yawn, i think itd be fun to have Maths challenges on the bored, harder than this one though.

Show that
x^n + y^n = z^n
has no non-zero integer solutions for x, y and z when n > 2.
Another somewhat old chestnut, but plenty hard enough for anyone.

[Stewart]

Ok, here's one for you:

A man has two bags, in each he places a rock weighing exactly 20kg. Then he places each bag on a set of scales. The first bag weighs 20kg, but the second weighs 20.4kg. How is this possible?

Answer: There is a cat asleep (well, probably dead now, seeing as a 20kg rock has been dropped on him) in the second bag.

Isn't maths amazing?

[Scarlet Infidel]

Show that
x^n + y^n = z^n
has no non-zero integer solutions for x, y and z when n > 2.
Another somewhat old chestnut, but plenty hard enough for anyone.

Erm, well im stumped.

The rocks in a sack one on the other hand, i never forget the 'felis mortuus variable'.

[midzt]

Show that
x^n + y^n = z^n
has no non-zero integer solutions for x, y and z when n > 2.
Another somewhat old chestnut, but plenty hard enough for anyone.

is that Fermat's last theorum? -theres a poster in a maths room of it. always seem to look at it when im bored but have never really bothered actually proving it.

[Dougal]

Ok, here's one for you:

A man has two bags, in each he places a rock weighing exactly 20kg. Then he places each bag on a set of scales. The first bag weighs 20kg, but the second weighs 20.4kg. How is this possible?

Answer: There is a cat asleep (well, probably dead now, seeing as a 20kg rock has been dropped on him) in the second bag.

Isn't maths amazing?

Bloody small cat to weigh 400g.

I hate proof questions, I can do them but only after a loooong time.

[mike_w]

is that Fermat's last theorum? -theres a poster in a maths room of it. always seem to look at it when im bored but have never really bothered actually proving it.

Yes indeedy! And it took a few hundred years to solve (if memory serves), and the guy who did solve it took a decade of his life (again, if memory serves). I read a good book about it (of the same name, can't remember the author, but it was connected to Horizon... the same guy did the Code Book, I think).

[headbrace]

Show that
x^n + y^n = z^n
has no non-zero integer solutions for x, y and z when n > 2.
Another somewhat old chestnut, but plenty hard enough for anyone.

Haven't got space to write it out here, this margin is to small.

Although what you would probably want to do is show that the expression above can be written as an albeit complex elliptic equation. Then is' just a matter of solving the Taniyama-Shimura conjecture and finding a corresponding matrix or somesuch, and solving that, if it exists. Which it won't because it doesnt for n>2.

[herulach]

Yes indeedy! And it took a few hundred years to solve (if memory serves), and the guy who did solve it took a decade of his life (again, if memory serves). I read a good book about it (of the same name, can't remember the author, but it was connected to Horizon... the same guy did the Code Book, I think).

Simon singh yeah. And it take bloody ages wikipedia says 357 years, it also has some good reading on it.

This page has some pretty good ones, theres some crap ones too, have a hunt.

[mike_w]

Simon singh yeah. And it take bloody ages wikipedia says 357 years, it also has some good reading on it.

Wikipedia has some good reading on just about everything! I'll have a look at that page some time - thanks!

[smtkr]

When did ONE=TWO??

Just now

Let a=b...

Wait, are you hexus members just going to let this stand? I noticed a bunch of you were being tested in math for something (I am not familiar with the UK ed. system). I know you can see the obvious error in this solution...

[sdl]

Wait, are you hexus members just going to let this stand? I noticed a bunch of you were being tested in math for something (I am not familiar with the UK ed. system). I know you can see the obvious error in this solution...

herulach already gave the answer in the fourth post.

[Scarlet Infidel]

Exactly. Did anyone ever do maths challenge papers at school? I love those things.

[phunkygal]

Exactly. Did anyone ever do maths challenge papers at school? I love those things.

do you mean those national things where you got a gold/silver/bronze certificate...it was like a multiple choice test i think.

[Scarlet Infidel]

Yeh, those ones. And on the harder questions you actually lost marks for getting them wrong.