a man sets his watch by the sound of a siren placed 1km away. if velocity of sound in air is 330m/s how much error will his watch show?

 Time = distance / velocity

Here distance = 1km = 1000m and velocity = 330m/sec

Time taken by sound to reach the man = 1000/330 = 3.0303... = 3 sec approx

So the error will be 3 sec approx