A cannon is fired from town X; after how long is the sound heard at a town Y 4.95km away? [velocity of sound in the air = 330 ms−¹1]

A. 30s
B. 10s
C. 10s
D. 15s

Correct Answer:

Option A – 30s

Explanation

V = (2X)/t
330 = (2 x 4.95 x 10³)/t
t = (9.9. x 10³/330 = (9900)/330 = (90)/3
= 30 secs