<image> The line graph shows the situation of the 400-meter race between Li Fang and Wang Gang.
(1) Li Fang took ____ seconds to run 400 meters, and Wang Gang took ____ seconds.
(2) At the 30-second mark, Li Fang had run ____ meters, and Wang Gang had run ____ meters.
(3) In the first 200 meters, ____ ran faster.
(4) Wang Gang's average speed for the entire race was ____ meters per second.