To Dave Godfrey (Wednesday's letters): A "MB" is 1048576 "bytes" (or letters). Multiply this by the 800MB you can get on a modern CD then again by 2 for the number of CD's, and then divide by 25 million records you get about 67 letters per person. "zip" file compression would allow you fit say 4 times this in the same space, so that allows for over 250 characters per record. Plenty of space for a name, address and bank account.
Jonathan, Bury St Edmunds
Dave Godfrey (Wednesday's letters): Good question. I'll start by assuming you already know that we use CDs rather than floppy disks these days. I did a little experiment to see if the numbers make sense. I created a dataset with 25,000 copies of my own name, address, national insurance number, and bank details. It takes up about 1.3 MB on disk. 25 million records should therefore be about 1300 MB. A CD holds 650 MB, so there is in fact just enough room for 25 million records. It's a bit of a crude experiment, as I didn't put details of children on it, but I suspect children count towards the 25 million anyway so that probably doesn't make much difference. I'll get my anorak...
Adam, London, UK
Your obesity quiz is advertised as "A test on food, fat and health". However, most questions were related to percentages & statistics that have been reported in the media. I only got 2 correct because I hadnt read/remembered any of the relevant articles. Nothing in that quiz was useful to know, and is not going to help the problem of obesity.
Rhian, Nicosia, Cyprus
Ref: England failure 'may hit economy', Cheer up, there are some groups happy about last night's result, the Austria and Swiss police for one, all the other home nations for another.
The Earth's Moon is 'cosmic rarity'? Is it really such a rarity considering there are an estimated 130 billion solar systems with on average 300 billon stars per solar system so that's 5% - 10% of 39,000,000,000,000,000,000,000 planetary systems. I would almost certainly not consider that rare!
James Spencer, London
Here's an idea for a random stat: what proportion of the population has level knees? Judging by this pic not a lot.
Once again I misread one of your articles. I was looking forward to finally some material recognition of my contribution to society (mainly writing these letters), but, no, Britain's getting obese, not OBE's.
Rob Falconer, Llandough, Wales
In respect of the DMQ, are we to confront that guitar boldly?
Pete Cundall, Burgess Hill, West Sussex, UK