cts - two persons start walking from the same place in opposite directions such that one go towards east at 10 meters per minute and other goes towards west at 20 meters per minuteat what time will they be 72 km apart - skillgun

Total They have to walk 7200 meters so it takes 4 hours becoz one person move to east and walk 10 meters per minute and other person walk 20 m per minute I opposite direction.So it takes 4 hours .