Tourists covered 255 km for a 4-hour ride by car and a 7-hour ride by train. what is the speed of the train, if it is 5 km/h greater than the speed of the car?

The distance covered by car is equal to (assuming it is moving by uniform motion) the product between the car's speed and the time of the car ride, 4 h:

where
is the car's speed
is the duration of the car ride

Similarly, the distance covered by train is equal to the product between the train's speed and the duration of the train ride, 7 h:


The total distance covered is S=255 km, which is the sum of the distances covered by car and train:

which becomes
(1)
we also know that the train speed is 5 km/h greater than the car's speed:
(2)

If we put (2) into (1), we find

and if we solve it, we find



So, the car speed is 20 km/h and the train speed is 25 km/h.

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