1.  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 train (in km/hr), supposing that speed travels at 330 metres per second, is :
A. 19.8
B. 111.80
C. 59.4
D. 58.6

Answer: Option C

Explanation:

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.
<=>(X x 10 x 60) = (330 x 30) <=> X = 16.5

Speed of the train = 16.5 m/sec
= 16.5 x 18/5 km/hr
= 59.4 km/hr