Petty !

A man who paid 40 euro cents (65 cents) more than he expected for a call to a German television quiz show has filed fraud charges, police say.

Having devised a formula to answer the question "How much milk do 10 oxen produce in 10 minutes if five oxen produce five litres in five minutes?", the man went to a pay phone and made what he thought would be a 50 euro cents call.

However, he was angered when the cost came to 90 euro cents and even more incensed because the phone-in show said the question was actually a riddle with no answer.

"Don't forget that an ox is a castrated bull," a spokesman for police in the western city of Muenster said.

The man did not see the funny side and went to a police station at 3am (local time) to file charges.

Police and state prosecutors are now investigating whether he has a case.