Question: How did the dupont family make their fortune?
Disambiguated questions and answers: question: How did the dupont family make their original fortune?
How did the dupont family expand their fortune?
What are interests did the dupont family use to make their fortune?
answer: gunpowder business
chemical industry and the automotive industry
DuPont company, General Motors, and various other corporations
Natural Questions answer: black powder manufacturing (from the Wikipedia article "Du Pont family")