Now A is 872 meters away from the public toilet, and A runs to the public toilet at a speed of 45 meters per second.

B is 823 meters away from the public toilet. B runs to the public toilet at a speed of 89 meters per second, but B stops for 2 seconds every 3 seconds.

C is 749 meters away from the public toilet. The speed of C running to the public toilet is 122 meters per second, but C runs in the opposite direction every 4 seconds 1 second.

Ding is 639 meters away from the public toilet. Ding ran to the public toilet at a speed of 67 meters per second. Ding jumps forward every second, jumping 64 meters at a time.

A piece of 872/45= 19.38

b 823/3 * 89 = 3.08(3+2)* 3+(823-3 * 89 * 3)/89 = 15.25

c 749/ 122 *(4- 1)= 2.05(4+ 1)* 2+[749- 122 *(4- 1)* 2]/65438+。

d 639/(67+64)= 4.88 4 * 2+2 = 10

Ding Can took the first place in the public toilet.