<u>Answer</u>
The combined displacement is 2km north
<u>Explanation</u>
Since displacement is a vector quantity, we take into account the direction.
Good for us all the displacement vectors are in the same dimension, so we can make north positive and south negative or vice-versa.
We now add to obtain,

This will simplify to

Therefore the combined displacement is 2km north
It's 120N downwards. net force is adding or subtracting the x and y values