Meet the world's richest CEOs

They dared to dream. They dared to think out of the box and they dared to follow their gut. Today, they are the world's richest people.

In this complied list by CNBC, the world's 10 richest CEOs spans across four generations -- the youngest was born in 1984 and the oldest in 1930.

According to the study, the ranking is based on net worth figures from Wealth-X, a research firm that provides information on ultra high net worth individuals to private banks and consulting firms.

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Carlos Slim, 72
Net worth: $70 billion

Mexican tycoon, Carlos Slim is the richest person in the world for the third year in a row.

This immigrant son of Lebanese descent is the chairman and CEO of telecommunications companies Telmex and America Movil (AMX) and has extensive holdings in other Mexican companies through Grupo Carso SAB.

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Warren Buffett, 81
Net worth: $44.7 billion

Warren Buffet, the director and CEO of Berkshire Hathaway, is widely regarded as one of the most successful investors in the world.

He has also been consistently ranked among the world's wealthiest people.

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Lawrence Ellison, 67
Net worth: $35 billion

Lawrence "Larry" Ellison is the co-founder and chief executive officer of Oracle Corporation, one of the world's leading enterprise software companies. As of 2012, he is the third wealthiest American citizen.

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Eike Batista, 56
Net worth: $31.6 billion

A Brazilian tycoon, Eike Batista is the owner and president of EBX Group. As reported by Forbes, Batista vows to one day overtake Carlos Slim of Mexico as the world's richest man.

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Charles G Koch, 76
Net worth: $24.7 billion

Charles Koch is co-owner, chairman of the board and chief executive officer of Koch Industries, the second-largest privately held company by revenue in the US according to a 2010 Forbes survey.

Koch provides financial support for a number of public policy and charitable organisations, including the Institute for Humane Studies and the Mercatus Center at George Mason University. He also co-founded the Washington, DC-based Cato Institute.

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Sheldon Adelson, 78
Net worth: $24.6 billion

Sheldon Adelson is an American business magnate. He is the chairman and chief executive officer of the Las Vegas Sands Corporation, the parent company of Venetian Macao.

It is reported that Adelson vastly increased his net worth upon the initial public offering of Las Vegas Sands in December 2004.

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Lakshmi Mittal, 61
Net worth: $19.1 billion

Lakshmi Mittal is an Indian steel magnate. He is the chairman and chief executive officer of ArcelorMittal, the world's largest steelmaking company.

Mittal is the richest man in India, Asia and the UK and second in Europe and is presently the 6th richest individual in the world.

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Larry Page, 39
Net worth: $18.3 billion

Larry Page is an American computer scientist and internet entrepreneur, and is best known as the co-founder of Google.

After earning a Bachelor of Science degree in engineering from the University of Michigan, Page decided to concentrate on computer engineering at Stanford University, where he met Sergey Brin, with whom he co-foudend Google.

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Mark Zuckerberg, 27
Net worth: $18.1 billion

Mark Zuckerberg is best known for co-creating the social networking site Facebook, of which he is the chief executive.

In 2010, Zuckerberg was named Time magazine's Person of the Year. As of 2011, his personal wealth was estimated to be $17.5 billion, making him one of the world's youngest billionaires.

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Aliko Dangote, 55
Net worth: $11.2 billion

Aliko Dangote, is a Nigerian business magnate, who owns the Dangote Group. Dangote started trading commodities more than three decades ago after receiving a business loan from his uncle. He then built the Dangote Group, which in addition to cement owns sugar refineries, flour milling and salt processing facilities.

The group now has operations in his homeland and several other countries in Africa, including Benin, Cameroon, Ghana, South Africa and Zambia.