19. Numerical based on sound travel

1. A stone is dropped from the top of a well, which is 3500 $m$ high from the water surface.When is the splash heard at the top?($g$ = $10$$m/s²$ and speed of sound($v$) = 342 $m/s²$)

 

 

Thus, the total time taken by the splash sound to reach the top is  $s$