Why Bill and Melinda Gates put 20,000 students through college

America, built on the dream of upward mobility, has become a country of deepening divide between rich and poor. The surest way to narrow the wealth gap is to earn a college degree. Now major universities like Princeton are working to lower the price of admission through a new kind of affirmative action, not based on race, but on low-income status. It began with two of America's wealthiest parents, Bill and Melinda Gates. More...