Answer:
The velocity of wave is 2.4m/s.
Step-by-step explanation:
First, find the frequency using the formula :
![f = (1)/(t)](https://img.qammunity.org/2021/formulas/physics/middle-school/94czn5lps4x8hb1wim95gn0hp2xvw23zg4.png)
Let t = 4,
![f = (1)/(4)](https://img.qammunity.org/2021/formulas/physics/middle-school/n82g9xihdjfb066ag97uxqw44ywoqm49mt.png)
![f = 0.25Hz](https://img.qammunity.org/2021/formulas/physics/middle-school/ckdtunv7vj06v5ew3c0k49ga1u514syc0j.png)
Next, given that each wave is 1.2m and there are 8 waves so the wavelength is :
![λ = 1.2 * 8](https://img.qammunity.org/2021/formulas/physics/middle-school/pxexwzw520hm5b066yqw01bnq93g5q8ur5.png)
![λ = 9.6m](https://img.qammunity.org/2021/formulas/physics/middle-school/g6aj04nxbj7n4pgvim6oarpkeh9r3acyj4.png)
Lastly, you have to use velocity formula :
![v = f * λ \:](https://img.qammunity.org/2021/formulas/physics/middle-school/1ch4ma99axi896ot2vz9mikn314lozttrw.png)
Let f = 0.25Hz,
Let λ = 9.6m,
![v = 0.25 * 9.6](https://img.qammunity.org/2021/formulas/physics/middle-school/m6kn66brovq0wl1uueri35idb6zonf0cv5.png)
![v = 2.4](https://img.qammunity.org/2021/formulas/physics/middle-school/2d8we0io6vtzmb54ceotq2rfevnk4fv9qz.png)
(Correct me if I am wrong)