How long did it take for Li Bing to create his irrigation channel?​

about seven years

Explanation:

The cracked rock was cleared away and the process started all over. It took about seven years to cut a channel through the rock.

Over 2,200 years ago, the city was threatened by the frequent floods caused by flooding of the Minjiang River (a tributary of the Yangtze River ). Li Bing, a local official of Sichuan Province at that time, together with his son, decided to construct an irrigation …

Explanation:

map scale refers to the relationship (or ratio) between distance on a map and the corresponding distance on the ground. for example, on a 1: 100000 scale map, 1cm on the map equals 1km on the ground.