A boy standing in front of a wall produces two whistles per second. He notices that the sound of his whistling coincides with the echo. The eacho is heard only once when whistling is stopped. Calculate the distance between the boy and the wall. (The speed of soudn in air = 320 m/s)
If the speed of sound is increased by `16 ms^(-1)` and the boy moves 4 m away from the wall then in how much time will he hear the echo of the first whistle ?

Options

A. 0.525 s
B. 0.5s
C. 0.48s
D. 0.3s