How is the motion of a point having a constant phase measured?

$A$ travelling wave pulse is given by $y = \frac{4}{3x^2 + 48t^2 + 24xt + 2}$,where $x$ and $y$ are in $m$ and $t$ is in $s$. The velocity of the wave is ........... $m/s$.

Two waves are represented by: $x_1 = A \sin \left(\omega t + \frac{\pi}{6}\right)$ and $x_2 = A \cos \omega t$. Then the phase difference between them is

An observer standing near the sea shore observes $54$ waves per minute. If the wavelength of the water wave is $10 \ m$,then the velocity of the water wave is .... $m/s$.

If a travelling wave is given by $y(x, t) = 0.5 \sin (70.1 x - 10 \pi t)$,where $x$ and $y$ are in metre,the time $t$ is in second,then the frequency of the wave is (in $Hz$)

The equation of a progressive wave is $y = 4 \sin(4 \pi t - 0.04 x + \pi / 3)$, where $x$ is in meters and $t$ is in seconds. The velocity of the wave is: