Lynsi Torres, the owner and heiress of In-N-Out Burger, is the youngest American female billionaire. Torres does not have a college degree or much formal management training. Thanks to In-N-Out's large fan base at its nearly 280 restaurants in five states, the chain is now worth roughly $1.1 billion, according to estimates -- 19,298 times more than the median U.S. household in 2010.

Women in Business, Business, Business Leadership, Business Growth, Female Leadership, Food industry, Fast Food,