Can you solve it? Puzzles you can do in the pub

Test yourself against the readers of New Scientist magazine

UPDATE: To read the solutions click here

Pubs are for drinking, socialising - and doing puzzles. Or so claims Headscratchers, a new compendium of puzzles from New Scientist magazine, from which today's cranium-ticklers are taken.

The first is a classic pub puzzle. (An inn-igma? a bam-booze-ler? A conun-dram?) Which is to say, it is a mathematical challenge that lends itself to being tackled in a group, and may lead to heated debate!