The distance from Ammu's house to Ashwati's house = 5.6 km
The distance Ammu has to cover more by going through the longest path = 2700m
Let's convert all the units to km.
1000m = 1km
2700/1000 = 2.7 km
The total distance Ammu has to cover = 5.6 + 2.7
5.6
+2.7
_____
8.3
So Ammu has to travel 8.3 km to reach Ashwati's house while going through the longest path.