Two guns were fired from the same place at an interval of 10 minutes and 30 seconds, but a person in the train approaching the place hears the second shot 10 minutes after the first. The speed of the trian (in km/hr), supposing that speed travels at 330 metres per second, is:
Choose the correct answer
A) 50.4	B) 111.8	C) 19.88	D) 59.4	E) None
Sol.   Let the speed of the train be x m/sec. Then,   Distance travelled by the train in 10 min. = Distance travelled by sound in 30 sec.   ∴ Speed of the train = 16.5 m/sec = [16.5*18/5] km/hr = 59.4 km/hr   Answer 59.4
<result>D</result>
Two guns were fired from the same place at an interval of 10 minutes and 30 seconds, but a person in the train approaching the place hears the second shot 10 minutes after the first. The speed of the trian (in km/hr), supposing that speed travels at 330 metres per second, is: