A train leaves and travels N at 70 kilos per hour. Another train leaves at the same time and travels S at 85 kilos per hour. How long will it take before they are 310 kilometers apart?
One train travels north at 70 kph
The other train travels south at 85 kph.
Relative speed of the two trains is 70 + 85 = 155 kph
i.e. they are travelling apart at a speed of 155 kph.
When the distance between then is 310 km,
Time taken is t = 310/155 = 2 hrs
Time taken = 2 hrs