School leavers trying to get into Oxbridge get asked an extraordinary array of questions at interview, it has been revealed.

They range from teasers about the percentage of the world's water contained in a cow to philosophical posers about the nature of cool.

They are tricky enough for a nervous 17-year-old but how about the rest of us? And do rocket scientists and brain surgeons fare any better than the rest of the population?

Valentine Low and Robert Mendick grilled a few likely contenders.

What percentage of the world's water is contained in a cow? (veterinary medicine, Cambridge)

Rocket scientist Professor Colin Pillinger, the man behind the Beagle 2 Mars project: "The human body is 70-80 per cent water, and I am sure a cow is not too different.

"You would make a stab at how much water there is on the Earth, and how that compares to the mass of a cow.

"If you work out that two-thirds of the earth's surface is water and you know the diameter, you can calculate it from that."

Comedian and writer Meera Syal: "You would have to distinguish between an Indian and an English cow.

"An Indian cow would be eating and drinking things it shouldn't."

If there were three, beautiful naked women standing in front of you, which one would you pick? Does this have any relevance to economics? (philosophy, politics and economics, Oxford)

Professor Pillinger: "Do you want your washing and ironing done, or are you going to spend your life thinking about the quarter of an hour you spend indulging in some other form of entertainment?"

Brain surgeon David Choi, consultant neurosurgeon at the National Hospital for Neurology and Neurosurgery: "If I was looking for a date I would probably go for the most beautiful ... or the one that I was most compatible with. "

Bettany Hughes, historian and broadcaster, Studied Ancient and Medieval History at New College, Oxford: "I would have a bit of a lesbian something going on with this one. I would find a reason to pick all of them to justify taking all three of them home. "

Why can't you light a candle in a spaceship? (physics, Oxford)

Professor Pillinger: "The atmosphere in there is probably a synthetic atmosphere with a lot of oxygen in it. It might well flare up and do a lot of damage. "You certainly cannot light a candle outside a spaceship."

Jilly Cooper: "You can't have a birthday on a spaceship no birthday cake. If you spent a year in space you would be really screwed."

Are you cool? (philosophy, politics and economics, Oxford)

Meera Syal: "I suppose the definition of being cool is thinking you're not."

"Mad" Frankie Fraser, former East End villain: "That's a good 'un. I will have to ask the governor of Dartmoor if he thinks I am cool."