Does my work make sense?

A turnbuckle is needed to apply an 8kN force on a cable. If the efficiency of the turnbuckle is 40% and the force applied is 159.155N with a lever of 20cm in length.
a) Find the mechanical advantage.
Mechanical Advantage=Load/Effort
M.A.=8000N/159.155N
M.A.=50.265 (Ans.)
b) Find the velocity ratio.
Efficiency(ç)=(Mechanical Advantage)/(Velocity Ratio)
V.R.=(M.A.)/ç
V.R.=50.265/0.40
Velocity Ratio=125.66 (Ans.)
c) Find the mean pitch of thread.
V.R.=(Distance moved by effort)/(Distance moved by load)
V.R.=2ðL/(2Xpitch of thread)
2Xpitch of thread=2ðX200mm/126.66
2Xpitch of thread=1256.637/126.66
Pitch of thread=9.921/2
Pitch of thread=4.96mm (Ans.)