Billionaire Bill Gates Speaks At The Sibos Conference [Getty Images]

Billionaire Bill Gates, co-founder of Microsoft and co-chair of the Bill and Melinda Gates Foundation, smiles before an interview with Bloomberg Television at the Sibos financial services conference in Boston, Massachusetts, U.S., on Thursday, Oct. 2, 2014. Gates said he is "very happy" with Microsoft chief executive officer Satya Nadella and he is working with the company to improve it's Office software. Photographer: Kelvin Ma/Bloomberg via Getty Images

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