Virgin founder Richard Branson says that a rule requiring an equal number of female executives in boardrooms could benefit American businesses. “In Scandinavia, the government forces company boards to have 50 percent women, 50 percent men. And it works because companies that have women on their boards . . . are better-run companies. A law like that in America would be a good thing, ” he told us at an event for his book “Like a Virgin: Secrets They Won’t Teach You at Business School.” Yesterday afternoon, the British billionaire doled out tips to business owners from atop a replica of the upper class of a Virgin Airlines plane in the rain in front of the New York Stock Exchange.