Question

an Echo of a sound is heard after 3 s. find the distance of the reflecting surface from the source if the speed of sound in air is 340m/s

Answer 1

GIVEN:
 t=3s
 v= 340 m/s
 d=?

SOLUTION:

2d=v*t
2d=340*3
  d=1020/2
  d=510m

Answer= 510m

Answer 2

V = 2d/t [formula]

Given :
V = 340
 t = 3
D = ?


Solution :

V = 2d/t
340 = 2d/3
1020 = 2d [cross multiplication]
510 = d [division]

Final answer : 510m

                                     Hope it helps....................