Conversation so far:
What years did Bob Hayes participate in the Olympics?
Bob Hayes represented the United States at the 1964 Olympics, in Tokyo.
What events did Bob Hayes participate in, in the 1964 Olympics?
Bob Hayes participated in the 100m, and the 4×100 meter relay at the 1964 Summer Olympics, in Tokyo.

Question: How many olympics did he participate in?
Self-contained rewrite: How many olympics did Bob Hayes participate in?