Answer:
200 m/s
Step-by-step explanation:
We are given that
Length of string=L=1.5 m
Number of antinodes=n=3
Frequency of the wave=f=200 Hz
The relation between the length and wavelength

Using the formula


The relation between the velocity,frequency and wavelength

Using the formula

Hence, the speed of the wave on the string=200 m/s