Answer:
[tex]5\ \text{km}[/tex]
Step-by-step explanation:
Distance between Ace Supermarket is [tex]3.25\ \text{km}[/tex] north of city hall and the post office is [tex]1.75\ \text{km}[/tex] south of city.
This means that the city hall is in between the Ace Supermarket and post office.
Hence, the distance between the Ace Supermarket and post office is [tex]3.25+1.75=5\ \text{km}[/tex].