200× 3 = 600 meters

250-200 = 50m

600 ÷ 50 = 12 minutes

12× 250 = 3000m [distance run by two people]

② Problems

4× 5 = 20

32-20 = 12

At this point, the known conditions can be transformed into

Four secondary pastry chefs can make four cages of steamed bread every ten minutes, 12 more;

Five secondary pastry chefs can make six steamed buns in ten minutes, which is 30 less. Divide the above known conditions by the number of people and calculate the number of people, so you can know how many steamed buns are in each cage.

There are x steamed buns in each cage.

4X+ 12=6X-30

X=45

① Xinglong Mine of Yankuang has been solved.