To solve this problem, we can use the concept of relative velocity.
First, let's find the length of the train by converting the speed of the train from km/h to m/s.
72 km/h = (72 * 1000 m) / (60 * 60 s) = 20 m/s
Since the train passes the pole in 3 seconds, the length of the train can be calculated as:
Length of train = Speed * Time = 20 m/s * 3 s = 60 m
Now, let's consider the train passing the bridge. The train passes a total distance, which is the sum of the length of the train and the length of the bridge.
Total distance = Length of train + Length of bridge
Total distance = 60 m + 540 m = 600 m
We need to find the time taken by the train to pass the bridge. Time is equal to distance divided by speed.
Time = Total distance / Speed = 600 m / 20 m/s = 30 s
Therefore, the train will take 30 seconds to pass the bridge.