Riddle: Three cars had driven into a parking lot at the same time, and the three drivers left them all for the attendant to park. Unfortunately, he isn't too good at remembering exactly which driver drove which car. However, he is sure of these 6 facts:  a. Colin drove the BMW if and only if Mr. Cooper drove the Avenger. b. Alan drove the Cortina if and only if Mr. Cooper drove the BMW. c. Colin is Mr. Brown if and only if Mr. Andrews drove the BMW. d. Brian is Mr. Andrews if and only if Colin drove the BMW. e. Mr. Cooper drove the Avenger if and only if Alan is Mr. Brown. f. Colin is Mr. Brown if and only if Alan drove the Cortina.  Who arrived with which car?
Answer: Brian Brown drove the BMW, Alan Andrew's drove the Avenger, and Colin Cooper drove the Cortina