Elliot the detective heard the news of a double murder that occured on a train. The driver and the conductor were on the opposite sides of the train, but both were shot at the same time, reported a policeman who was at the center of the train at the time. The policeman had heard both gunshots at the same time. The train was travelling 150 kilometers per hour. Elliot immediately realized that the driver and the conductor were not killed at the same time. How is it so?
The train was going at 150 km/h, so the sound of the gunshot in the front of the train would reach the policeman's ears faster than the gunshot from the back of the train. So the conductor was shot first.
Today's brain teaser courtesy of Braingle.com.