Calculating Frequency of a Transverse Wave on a String

[dietcokegal]

Homework Statement

A periodic transverse wave is established on a string such that there are exactly two cycles traveling along a 3.0m section of the string. The crests move at 20 m/s. What is the frequency of the wave?

Homework Equations

?

The Attempt at a Solution

Dont know how to do it.

 

[Feldoh]

Let's take the problem apart a bit. for starters if there are two cycles in a 3.0m section that's essentially saying that 2*wavelength = 3.0m, right?

Now, how do we find frequency from wavelength?