Final answer:
James Farmer was the co-founder of CORE who organized the Freedom Rides to challenge segregation in interstate travel.
Step-by-step explanation:
The co-founder of CORE who organized the Freedom Rides was James Farmer. He became the leader of CORE in 1961 and organized groups of white and black students to challenge segregation in interstate travel in the Deep South. The Freedom Rides were a series of protests that aimed to test the federal government's ruling against segregation in interstate transportation.