# Letters

Issue 6## Why stop?

The PASS Maths "magazine" is great! Why did publishing stop with the May '98 issue?

**Jon Revelos**

*It didn't, PASS Maths is still going strong. We publish once per term: January, May and September. A new editorial team will be publishing the January 1999 issue, see "Time to change" in the issue 7 Editorial.*

## Probabilities

I would like to know how many chances there are of guessing a number with four digits.

My cousin says that there are one in ten thousand chances of guessing, but I think that there is much more. Can you give me the answer?

**F. Ferretti**

*Your cousin is right if you include all four-digit sequences from 0000-9999. If he/she chooses one of them at random then the chances of you guessing which one was chosen first time is 1 in 10000. That is because there are 10000 equally likely possibilities and only one of them is the right one!*

*If you do not allow numbers with leading 0s, the normal meaning of "four digit numbers", then there are only 9000 equally likely possibilities: 1000-9999 and the chances are therefore 1 in 9000.*

## PASS Maths new look

The outlook of the site has improved. More interesting puzzle problems could be put in.

**Michael Deutschemann**

**How to contact us:** Any comments?