I have 3 variables...

[Terbinator]

No programming, don't worry.

But say for example i had the security code for a 'card' and it was 3 different numbers to make up the three figure number would the amount of possibilities be: 9x9x9=724? which i don't think it is as on the face of it, as the values can range from 000-999.

Or is it 9^9= 387420489? (may of gone one 'x9' too many there )

Or something completely different?

Disclaimer: I am not asking for illegal purposes, but someone's post on FB about an apparent leaking of credit card numbers (by anonymous) did prompt this thought into ones mind.

[Lucio]

What you need here is combination theory

http://en.wikipedia.org/wiki/Combination

If I remember my statistics a-level, it'll be (9*8*7*6*5*4*3*2*1) / (3*2*1) or 60,480 different combinations.

[GoNz0]

2nds on the spliff dood.

[Terbinator]

2nds on the spliff dood.

I can now sleep easy

[scaryjim]

assuming you have 3 numbers, each of which can be 0-9 (i.e. 10 possible values), then the number of possible different combinations is 10^3 or 1000 (which is pretty obvious if you think that it can be any number between 0 and 999....).

[Terbinator]

A challenger appears xD

Edit: If that is the case it seems like such a paltry amount of numbers given the item it should be protecting, IMO.

[AD-15]

assuming you have 3 numbers, each of which can be 0-9 (i.e. 10 possible values), then the number of possible different combinations is 10^3 or 1000 (which is pretty obvious if you think that it can be any number between 0 and 999)

In that case, it would be 999 (1000 is a four digit number ).

However, the OP stated that the 3 numbers are different - so you couldn't have (for example): 111, 112, 099, 444, 696 etc...).

[Terbinator]

In that case, it would be 999 (1000 is a four digit number ).

However, the OP stated that the 3 numbers are different - so you couldn't have (for example): 111, 112, 099, 444, 696 etc...).

Good point, i should have articulated my original idea better

I guess we can work with both concepts though.

[jim]

If the three numbers are different, then it would go like this.

The first number can be any of 10.
The second number can't be the same as the first, so it can be any of 9.
The third number can't be the same as the first or the second, so it can be any of 8.

Therefore 10*9*8 = 720.

In that case, it would be 999 (1000 is a four digit number ).

I don't get what you're saying there. You realise that 000 also counts as one of the options, making 1000 alternatives?

[AD-15]

I don't get what you're saying there. You realise that 000 also counts as one of the options, making 1000 alternatives?

Bah. I was tired.

[Zhaoman]

yeah snootyjim has got it spot on. Is it normal to suddenly feel nostalgic for maths class?

[Terbinator]

yeah snootyjim has got it spot on. Is it normal to suddenly feel nostalgic for maths class?

Probably, can't believe it was nearly 5 years ago i was in my last one

[scaryjim]

Probably, can't believe it was nearly 5 years ago i was in my last one

5? Try it being 15 years ago...

[Phage]

5? Try it being 15 years ago...

28...

[Terbinator]

I don't remember writing "retirement castle" in the thread title guys

[scaryjim]

I don't remember writing "retirement castle" in the thread title guys

And whose fault is that, you young whippersnapper?! Get off of my lawn! And turn that "music" down