Combination calculation ?

Emp_Fab

Basically, I'm trying to work out how long it would take me to try every combination on a key-safe.  My sister-in-law has one on her outside wall that was there when she moved in, and she has no idea of the combination.  I want one to put on my mother's house.

So... if I can get my sister-in-law's one open, I can relocate it to mum's.

Now... as far as I know, it'll be either a 3 or 4 digit code, using numbers from 0 to 9 - but - the order of the numbers is irrelevant.  These things work on which buttons have been pressed - not what order, so for example, 123 is exactly the same combination as 132, 213, 231, 312 and 321 - which significantly reduces the number of permutations.  How may combinations are there ?

Your time starts.... NOW!!

stickyfiddle

If it's definitely a 3 or 4 digit code then it's 10*9*8/3 plus 10*9*8*7/4, which is about 1,500 combinations. 

Best get cracking then! Or google and see if there's a way of resetting them in exactly this scenario.

EDIT - there's a LOT of this stuff on youtube. An hour spent looking at videos could save you a lot of effort.

EDIT2, my calls were wrong, I think I fixed it. Probably

Paul_C

it shouldn't take that long to work through each combination - I've had to open a couple of Gibson cases by starting 001 002 003 etc. and getting to a number in the 700s only took about half an hour.

Sporky

Aren't they about £17 from Amazon?

mike_l

Sporky said:

Aren't they about £17 from Amazon?

Don't, If he gets anewone from Amazon he won't be able to put off trying to figure out the combination.
For 6 years.

Flink_Poyd

Interesting, there's one on the back of my house from the previous owner. Might have a crack at it to see if it's got a key in

SteveRobinson

Paul_C said:

it shouldn't take that long to work through each combination - I've had to open a couple of Gibson cases by starting 001 002 003 etc. and getting to a number in the 700s only took about half an hour.

It's easier than that. If you put a thin piece of metal down the side of each tumbler in turn you can feel when it's in the open position.

ICBM

SteveRobinson said:

Paul_C said:

it shouldn't take that long to work through each combination - I've had to open a couple of Gibson cases by starting 001 002 003 etc. and getting to a number in the 700s only took about half an hour.

It's easier than that. If you put a thin piece of metal down the side of each tumbler in turn you can feel when it's in the open position.

I've just done one by my usual method of forcing the tab back as hard as possible and then feeling which of the wheels is taking most of the load - because they're fairly poorly-made, there's a lot of slop in the mechanism - and turning that one until it clicks into place, then repeat with the other two. I got it open in about ten seconds.

fob

11,000 - no?

1000 combinations if it's a 3 digit code; 10,000 if it's 4 digits.

Are they push/digital buttons or a dial?

Sporky

fob said:

11,000 - no?

1000 combinations if it's a 3 digit code; 10,000 if it's 4 digits.

Are they push/digital buttons or a dial?

That's the difference between permutations and combinations.

In this instance, 123 is the same as 132, 213, 231, 312 and 321.

fob

I don't know what the safe is but if the code is 123 it's unlikely that 321 would work.

Sporky

If you did know what the safe was you'd understand that if the code was 123 then 321 would also work. Maybe you should re-read the first post.

Emp_Fab

It willfob said:

I don't know what the safe is but if the code is 123 it's unlikely that 321 would work.

It will.  That's how these ones work.  Even the instructions tell you the order is unimportant.

Paul_C

If it was three numbers then a normal combination lock would give you 000 to 999 which is 1000 combinations but each group of three covers six different possibilities so 1000/6 = 166.6 . . . except that 000 111 222 etc. only have one combination and 122 only has three so it's a little more than 166 in the end, maybe 180 or so ?

ESBlonde

My mother had a push button jobbie which required the final two numbers to be pressed simultaneously. What does that do for the possibility of getting it open. It wasn't always easy and I knew the combination!

mart

If it's 3 digits then there are 220 such combinations. If it's 4 digits, then there are 715. Full gory details of the calculation available if you really want it.