395 meter

.

The train moved 25 meter / sec.

From nose to tail it takes 130 / 25 = 5.2 seconds.

The remaining 21 - 5.2 = 15.8 seconds is the width of the bridge

=> 395 meter

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A train 130 m long passes a bridge in 21 seconds moving at a speed of 90 km/hr. Find out the length of the bridge.

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