A two-wheel drive tractor is operating a mould board plough at an average speed of $4 \mathrm{~km} \mathrm{~h}^{-1}$. The draft and the rear axle torque are found to be $30 \mathrm{kN}$ and $25 \mathrm{kN} \mathrm{m}$, respectively. If the rolling radius of traction wheel is $0.7 \mathrm{~m}$ and the wheel slip is $20 \%$, the tractive efficiency in percent will be
(A) 67.19
(B) 46.71
(C) 72.87
(D) 84.00
A two-wheel drive tractor is operating a mould board plough at an average speed of $4 \mathrm{~km} \mathrm{~h}^{-1}$. The draft and the rear axle torque are found to be $30 \mathrm{kN}$ and $25 \mathrm{kN} \mathrm{m}$, respectively. If the rolling radius of traction wheel is $0.7 \mathrm{~m}$ and the wheel slip is $20 \%$, the tractive efficiency in percent will be
(A) 67.19
(B) 46.71
(C) 72.87
(D) 84.00