Train Your Brain

So The Independent put out a book a couple of weeks ago, with their Saturday edition, called Train Your Brain in 7 days. There was an interactive CD on the Sunday and a pile of wall charts, etc. during the following week. I'm frequently fretting that the old grey matter is not getting nearly enough aeorbercising these days, so I threw down my £1.40 and prepared to get those synapses sweating. Second question into the exercise book (SECOND QUESTION!) and I'm already stumped.

Personal vanity aside, I'm on my knees begging - someone explain this to me please!!!!!!

Q: A bottle of wine weighs 1kg plus half it's own weight. How much does it weigh?

Ans: 2kg.

It's enough to put a gal off drinking.