Final answer:
The scale in this case is 1 cm on the map corresponds to 40 km in the actual distance.
Step-by-step explanation:
The scale in this case is found by setting up a proportion using the given information. We know that 3 cm on the map corresponds to 120 km in the actual distance. So, we can set up the proportion:
3 cm 120 km
------------ = ------------
1 cm x km
Cross multiplying, we get 3x = 120.
Dividing both sides by 3, we find that the value of x is 40.
Therefore, 1 cm on the map corresponds to 40 km in the actual distance.