Math problem: The time and distance of Chang 'e-2 satellite, which was launched by China, flying around the moon in an orbit about 100 km from the surface of the moon are as follows.
15 to 1 30 to 2 45 to 3 60 to 4 75 to 5 90 to 6.
Each ratio represents speed.
In direct proportion. Because flight distance/flight time = flight speed (certain)