Think twice next time someone asks you for "five minutes of your time" it could cost you more than you think. A British professo

Think twice next time someone asks you for "five minutes of your time", it could cost you more than you think. A British professor has developed a mathematical formula to help people find out exactly how much an hour of their time is worth. Professor Ian Walker of Warwick University investigated the value of time after research showed that over 80 percent of respondents would buy more time if they could afford it. "Traditionally, wages or salaries have given an indication of how we are valued at work," Walker, an economics professor, said in a statement. "However, by looking at salaries against taxation, the cost of living and regional variations, we can see how much an hour of our time is worth whether at work or home." The formula could help in making decisions, such as whether to cook a meal or to get a takeaway, or whether to take public transport or a taxi.  Visitors to www.Barclaycard.co.uk/timeismoney can find out the value of an hour of their time by entering their salary, the region where they work and what kind of work they do. For example, for a professional working in London and earning 25,000 pounds a year, an hour would be worth 6.44 pounds, according to the Web site. Cooking dinner would cost 5.37 pounds—cheaper to get a takeaway, once you add the cost of the raw materials needed to make it yourself. Brushing your teeth comes at 32 pence—perhaps hard to find someone to do it for you for less.