According to the Airports Council International, the busiest airport in the world is Atlanta’s Hartsfield International Airport, and the second busiest is Chicago’s O’Hare Airport. Together they handled 150.5 million passengers in the first six months of 1999. If Hartsfield handled 5.5 million more passengers than O’Hare, how many were handled by each airport? Let a = Atlanta’s Hartsfield; c = Chicago’s O’Hare. Which system is a correct representation of the problem?