Zero in pin code

JimmyTheWig

Martin (I believe) wrote this on Twitter...

A friend just revealed one of his pin numbers is a 0. Am too tired to work out what my odds of correctly guessing it are now.

I'm not on Twitter, but wanted to give the answer of 1 in 3439.

The pin could be one of
0[0-9][0-9][0-9]
[1-9]0[0-9][0-9]
[1-9][1-9]0[0-9]
[1-9][1-9][1-9]0
The first of these has 1000 options.
The second has 900 options.
The third has 810 options.
The fourth has 729 options.

[If he said that exactly one of his digits is zero then the odds of guessing it would be 1 in 2916.]

Derivative

Guessing PIN codes is really quite hard - at least in normal circumstance.

Even if I told you my first two digits were 00, you have 100 combinations to check. Three would get you blocked from an ATM, so you'd be running about for a while...

Mobeer

You need a bit more social engineering. If he's a trekkie, try 1701?