Explanation
The actual distance on the map = 13 cm
The map is drawn at a scale of 1 : 50, 000
On the map
1 cm on map represents 50, 000 cm
Therefore,
13cm on map represents 13 (50, 000) cm in actual distance on map
= 650, 000 cm in actual distance on map
= 6, 500 m in actual distace on map
= 650 km in acutal distance on map