Answer:
The scale used is 1: 10,000 cm.
Explanation:
Given that the length of a pool 2 km long is represented on a map with a length of 20cm, to determine what is the map scale used the following calculation must be performed:
2 km = 2,000 m
1m = 100cm
2,000 x 100 = 200,000
20: 200,000
10: 100,000
1: 10,000
Thus, the scale used is 1: 10,000 cm.