500
Al, Brad, Chuck, and Dirk all got new caps. Al and Dirk exchanged caps. Brad and Chuck exchanged caps. Finally Al and Brad exchanged caps. Al ended up with a red cap, Brad with a green cap, Chuck with a black cap, and Dirk with a blue cap. What cap did each boy have originally?
What is Al, blue. Brad, black. Chuck, red. Dirk, green.