Here is your answers worked out !
Answer:
4 km
Step-by-step explanation:
1000m:3m = 4000m:12m
For this case we must simplify the following expression:
We eliminate the parentheses taking into account that:

So:

We add similar terms taking into account that:
Equal signs are added and the same sign is placed.
Different signs are subtracted and the major sign is placed.

Answer:
