A $3-$phase induction motor is being driven at a frequency of $90$ Hz$,$ and the motor speed is $800$

rpm$.$

a$)$ How many poles does the motor probably have and what is the slip? $(5$ points$)$

b$)$ If we wanted to keep the same slip but increase the speed to $1200$ rpm$,$ what should be the electrical

frequency in Hz$?(5$ points$)$