Water Wave Problem: Calculating Fraction, Period & Frequency

[metalmagik]

The time needed for a water wave to change from the equilibrium level to the crest is 0.18 secs
a. What fraction of a wavelength is this?
b. What is the period of the wave?
c. What is the frequency of the wave?

This is more advanced than anything we've learned with waves as of yet. And it's for homework. Any hints and advice to get this started would be GREATLY appreciated.

 

[Doc Al]

Start by reading this: http://www.physicsclassroom.com/Class/waves/U10L2a.html.