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A certain thing is thrown twice from a place with the gap of 45 minutes between the two shots. A girl approaching this point in a train heard the second shot 44 minutes after she heard the first shot. What is the speed of train (in kmph) if sound travels at 660 m/s? a) 62 km/hr b) 54 km/hr c) 48 km/hr d) 27 km/hr
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B

Actual time between the two shots being fired = 45 minutes.

If a girl was stationary she would have heard the shots after 44 minutes. But since the train was moving

towards the source,

she heard the second shot after only 44 minutes = Distance travelled by the sound in 1 min.

the train speed .

=1/44 * (Speed of sound)

= 1/44 *(660)

=15 m/s

Convert m/s into km/hr

15 m/s = (15 *18/5) km/hr

=54 km/hr

Hence the speed of the train is 54 km/hr
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