Find the speed of a wave.

To solve that we get given that a wave generator produces three waves per second at a wavelenght of 1.2 meters.

To tackle this you can use the formula v= f * lambda (speed = frequency * wavelength)

In preparation for using this formula you need to calculate the frequency of the waves: by using frequency = number of waves / time passed which will result in 3 s^-1 .

Now using the speed formula we will yield a speed of 3.6 m/s or respectively 1km/h