Answer:
0.08
Step-by-step explanation:
this problem assume that both of whale and submarine are in rest position or in constant linier motion in same direction and same speed.
The sound will travel from Submarine to the whale and back again to submarine. so the time will be like this
t = 2d/v
t = 2*58.8/1520
t = 117.6/1520
t = 0.077368 s
t ≈ 0.08 s (less then 1 s)