This Michigan native is one of the cofounders of Google, which has made him the 11th richest person in the world. He is now the CEO of Alphabet, under which Google falls, and is also the creator of Google’s SEO algorithm PageRank.

This Brazil-born cofounder of Facebook has been the target of some criticism since earning his fortune: He renounced his US citizenship in 2011, which was largely seen as a way to avoid paying over $700 million in corporate gains tax.

This PayPal cofounder was also the first outside investor in Facebook, where he still retains a board seat. He’s also responsible for several Lord Of The Rings-themed ventures, such as Mithril Capital Management, Valar Ventures, and Palantir.

This Harvard dropout is one of the youngest tech successes in Silicon Valley, having grown FaceBook from a tiny “Hot-Or-Not” clone to the biggest social media platform on the planet.

While his early years may be the subject of some controversy, this social media master is now a dedicated philanthropist, having pledged to give most of his wealth away during his lifetime.

The Answers

Here are the solutions – how did you do?

1. Paul Allen

2. Steve Ballmer

3. Andreas von Bechtolsheim

4. Marc Benioff

5. Jeff Bezos

6. Sergey Brin

7. Michael Dell

8. Larry Ellison

9. Gabe Newell

10. Bill Gates

11. Jan Koum

12. Jack Ma

13. Dustin Moskovitz

14. Elon Musk

15. Pierre Omidyar

16. Larry Page

17. Eduardo Saverin

18. Eric Schmidt

19. Peter Thiel

20. Mark Zuckerberg