Solving for Distance of Iceberg from Ship: North Atlantic

[sp00ky]

A saling ship is traveling in the North Atlantic at night. The captain is worried about ice bergs, but has no radar. The captain sounds the ship's horn and hears the echo 2.4s later. If the air temperature is -10degrees Celsius, how far away is the iceberg. I think I know how to do it but still dont' get the right answer. This is what I did.
V = 331m/s + 0.58 m/s/Celsius * (-10Celsius)
= 325.1m/s
D = V(T)
= 325.1m/s * 2.4s
= 780.24m
How come it always comes with this answer.. The answer is like .39km or somethin' but I can't seem to get it

 

[Leong]

the distance you have found is the total distance the sound of the horns has traveled to reach the iceberg and to return to the captain. so you have to divide your anwer with 2.

 

[matt.o]

the sound wave has traveled twice the distance, since it has to travel to the iceberg and back for the captain to hear it. hence it really take 2.4/2 seconds to get to the iceberg.

D=325.2m/s * 2.4/2s
D=390.24m = .39024km