5x + 3 (x - y) - y =

8x - 4y?

Hey guys sorry I'm a little late but here goes the answer to all the problems you posted...which were laughably easy except for the horse one which is a little stronger.

I believe this is a possible choice but I'm not sure. You put one horse in the middle of the field and then encircle him inside 8 other stables, like this:

[H][H][H]
[H]H[H]
[H][H][H][H]

Then you have 8 stables making a larger 3x3 stable without the center panel, with the tenth horse in it to complete the stable.

Is it right?

For fuegonian's 3 [ 4 - 3 ( 6 - 7 ) ] = Correct procedure would be:

3[4-3(-1)]=
3[4+3]=
3[7]=
21// As easy as that. Of course it can be done mentally if you have a high enough level.

Now for fuegonian's 5x + 3 (x - y) - y = procedure is:

5x+3x-3y-y=
8x-4y=
4(4x-y)// And that's it.

Let's increase the level a little, ok? Here's an Olympiads first level problem:

If P=1x2x3x4...x50, then the number of factors 2 that P has is: ???

That problem should spice things up a bit.

Yeah, although I was an English major in college, math is my stronger subject.

Oddly enough, when I was 6 years old, I came down with a disease called Reye's Syndrome, and it made my brain swell up REALLY large and put me into a coma and nearly killed me.

While I was in a coma, I would see math equations in my head, and have horrible nightmares... but when I came out of the comma, apparently the swelling of my brain opened up the mathematical section of my brain. My mind, to this day, literally counts letters, objects, and what not without me even thinking about them.

What I mean is, my brain counts everything (especially letters for some reason) without me even trying. I can look at signs or anything and tell you how many letters are in it, the middle letter (the mean), averages.. well, everything, without even thinking about it.

Oddly enough, I literally am counting all of the time... I'm even counting things as I write this post. It's really odd, but I'm so used to it now, that I don't even notice it anymore.

On-topic: I'm thinking, but i'm sleepy and i don't know if i'll get anywhere with this problem lol

Oh my, is it 25?

That's very interesting Tovya. It's as if you gained the ability to use a part of the brain you hadn't been using before.
I know what you mean because a few weeks ago I didn't study mathematics heavily, but then I started studying really hard for the Olympiads, and now it's strange because I notice objects with square, triangle, rectangle, spherical or parabolical shapes and I think of them as mathematic problems; I never saw it like that before.

It's getting late so I'll be checking the answers tomorrow. Good night!

EDIT: Hehe that was my first answer too but it's wrong, try thinking a little more! I'll be checking tomorrow.

Yeah, that's all that I can figure really.

My wife thinks that part of me is kind of freaky, but she likes it when she needs a quick mathematical answer! LOL

I think the mind has abilities that can be unlocked under certain circumstances... sometime it's because we excercise that part of our brain, and other times it's due to trauma.

I've got it (I think)

P = 50!

= 2 * 25 * 49!

= 2 * 25 * 49 * 48!

= 2 * 25 * 49 * 2 * 24 * 47!

So the odd numbers never contribute any factors of 2 (odd * odd = odd)

And 50 provides 25 factors of 2

      48 provides 24

etc

So the answer is

1 + 2 + ... + 25

= 12.5*26

= 325

A+B+C = 21
A+B = 15
A+C = 17

Find A,B, and C