We know, length of segment wave is half the wavelength .
Let, wavelength of wave is
.
So, length of segment will be
.
Now, it is given that the string vibrates in four segments.
So,
![L = 4* (\lambda)/(2)\\\\L = 2\lambda\\\\\lambda = 1\ m](https://img.qammunity.org/2022/formulas/physics/high-school/xka8c056n9wh79372gst26k6ezh311450w.png)
Speed can be given by :
![speed = wavelength * frequency\\\\speed = 1* 120\ m/s\\\\speed = 120\ m/s](https://img.qammunity.org/2022/formulas/physics/high-school/sej0urvq04pgtha20h80onloy5hcazcgbo.png)
Therefore, the wave speed in the string is 120 m/s.