A $220-V,25-hp,60Hz,$ six$-$pole, Y$-$connected induction motor has the following impedances in ohms per phase referred to the stator circuit: $R_1=0\mathrm{.}3,R_2=0\mathrm{.}4,x_1=0\mathrm{.}4,x_2=0\mathrm{.}6$ and $x_m=15.$ If the motor runs at $1080$ rpm $,$ Calculate:

a$)$ Input current.

b$)$ Input power.

c$)$ Input power factor.

d$)$ Total developed torque.