Counting sheep

Pupils at the Oxford regional final of the UK Maths Challenge warmed up with this: "It is claimed that a lion can eat a sheep in four hours, a leopard can eat a sheep in five hours, while a bear takes six hours to eat a sheep. How long would it take all three of them to eat a single sheep?" After extensive displacement activity - ten minutes to make a cup of coffee and five minutes to hunt down and eat a chocolate biscuit - Diary got an answer. It will be printed next week. How quick were you? Aylesbury Grammar School won the regional final and will compete at the national final at King's College London on July 1.