The length of train is 120 meters
The speed of train is 25 meter per second
<u><em>Solution:</em></u>
The speed is given by formula:

Given that,
It takes a train 60 seconds to completely drive through a bridge of 1260 m
And 90 seconds to completely drive through a tunnel of 2010 m
Let the length of the train be "x"
<em><u>The total distance travelled by the train across the bridge is given by:</u></em>
total distance = x + 1260 + x = 2x + 1260
[ here we use x + x to represent that train completely drives through bridge ]
The time taken is given as 60 seconds
<em><u>Therefore, the speed is given as:</u></em>

<em><u>The total distance travelled by the train through the tunnel is given by:</u></em>
total distance = x + 2010 + x = 2x + 2010
The time taken is given as 90 seconds
<em><u>Therefore, the speed is given as:</u></em>

The speed of the train was the same in both cases.
Equate both speeds



Thus length of train is 120 meters
<em><u>Find the speed of train:</u></em>

Thus speed of train is 25 meter per second