Finding distance to fish from echo time 0.483 s

[BBboy]

I don't understand how I am suposse to solve this question using only 1 given
a) a deep sea fishing boat received an echo from a school of fish 0.483 s after transmission. How far away were the fish?
if anyone can help, it'll be appreciated

 

[Doc Al]

The sound (SONAR signal) must travel from boat to fish and back. How fast does sound travel in water?