To solve this problem we will apply the concepts related to wave velocity as a function of the tension and linear mass density. This is
[tex]v = \sqrt{\frac{T}{\mu}}[/tex]
Here
v = Wave speed
T = Tension
[tex]\mu[/tex] = Linear mass density
From this proportion we can realize that the speed of the wave is directly proportional to the square of the tension
[tex]v \propto \sqrt{T}[/tex]
Therefore, if there is an increase in tension of 4, the velocity will increase the square root of that proportion
[tex]v \propto \sqrt{4} = 2[/tex]
The factor that the wave speed change is 2.
