Question

The deepest part of the oceans in the world is the Mariana trench in the Pacific ocean. It is 11000m deep. How long will it take for sound transmitted by a ship, from above the trench to be reflected?

Answer 1

Speed of sound in water(v) = 1400m/s
Distance(d) = 11000m
time(t)= ?
from the formula of speed for echoes,
$t = 2d \div v \\ \: \: \: = 22000 \div 1400 \\ \: \: \: = 220 \div 14 \\ \: \: \: = 15.714s$
thus,
it will take 15.714 seconds

Answer 2

d=11000m  

speed of sound =1500m/s

v=2d/t

1500=22000/t

t=22000/1500  

t=14.6 s