The sound comes from the speakers which produce sound waves which is the music, the volume could be changed producing a louder sound or a quieter sound which means that the speakers could produce more sound waves or less sound ways ( depends on the volume )
Answer: a) 7,00 centimeters
(b) 259. 19 feet
(c) 3110.28 inches
(d) 0.049 miles
Explanation:
(a) We know that 1 meter = 100 centimeters
Therefore,

(b)Since 1 meter = 3.28084 feet
Then, 
(c) Since, 1 feet = 12 inches.

(d) 

15,000,000/300,000=50
It will take 50 seconds.