Waves, Bungee Jumping, Linear Density Definition

[alingy1]

Please look a picture.
I think the book made a mistake.
The answer should be 89.9N/m.
Why? Because they calculated the linear density μ wrongly. They should have done $$\frac{75*10^{-3}kg}{1.8m}$$

 

[SammyS]

Please look a picture.
I think the book made a mistake.
The answer should be 89.9N/m.
Why? Because they calculated the linear density μ wrongly. They should have done $$\frac{75*10^{-3}kg}{1.8m}$$

I'm pretty sure that you are correct !