Answer:
a.87.6 m/s
b.18.25 Hz
Step-by-step explanation:
the equation for the wave speed is expressed as

where v is the speed,
T is the tension in Newton
l is the length
and m is the mass
Now since

by substituting values into the equation, we have

b. the expression for the frequency is giving as
.
Note we 2L as the wavelength because we solving for the fundamental frequency as stated in the question.