Answer:
v = 9.34 m/s
Step-by-step explanation:
Given that,
The distance between crests,

The vertical distance from trough to crest = 3.6 m
Time taken, t = 1.5 s
The amplitude of wave = vertical distance from trough to crest /2
= 3.6/2
= 1.8 m
The speed of the wave is given by :

So, the speed of the wave is 9.34 m/s.