We assume that the problem is the following:

'A train normally travels 240 km at a certain speed. One day due to bad weather, the train's speed is reduced by 20 km/hr so that the journey takes 2 hours longer. Find the normal speed.'

Let 'v' represent the normal speed of the train, v>=0.

d = 240 km is the distance

v - 20 = the reduced by 20 km/hr speed

Since speed = distance/time follows time = distance/speed.

The time of the travel when traveling with normal speed v is: d/v

The time of the travel when traveling with reduced speed v - 20 is: d/(v - 20)

When the train's speed is reduced by 20 km/hr the journey takes 2 hours longer is represented by the equation:

d/(v - 20) = d/v + 2

plug the value for d into the last equation:

240/(v - 20) = 240/v + 2

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click here to see the equation solved for v

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v = 60 km/hr (We need to ignore the negative solution -40 because the speed can only be positive.)

The normal speed is 60 km/hr.