John D. Rockefeller is said to be the richest person ever to live, with an estimated wealth of $336 billion. But evidence suggests that an African named Mansa Musa probably surpassed that staggering amount. Musa lived in western Africa and became a surprisingly selfless emperor of the Mali people in 1312 A.D. By trading gold and salt, he amassed an enormous fortune, now estimated at $400 billion dollars in today's money. He is most famous for his pilgrimage to Mecca. Members of his caravan numbered some 60,000 people, and he made the journey with hundreds of animals and plenty of gold. He freely gave this gold to the poor that he met along the route. He had a number of mosques built, too. Legend has it that he built one every Friday during his reign. The most famous of these is the Djinguereber Mosque in Timbuktu, Mali.
What is the main idea of the passage?

Question

Quizplus · Accepted Answer

This sentence contains the main idea of the entire passage, as it is a statement that includes all of the most important ideas from the text.
Mansa Musa's caravan numbered some 60,000 people is incorrect. This is a supporting detail and is not the passage's main idea. 
Mansa Musa ruled the Mali people of western Africa is incorrect. This is an important point of the passage, but it fails to mention Mansa Musa's generosity. 
Legend states that Mansa Musa built a mosque every Friday is incorrect. This is a supporting detail and cannot be considered the main idea of the passage.

John D Rockefeller Is Said to Be the Richest Person Ever