Wait Lines

If the arrival rate of customers entering into a system is 4 per hour (assume Poisson Distribution), the service rate is 7 per hour (assume exponential distribution) and there are 2 channels operating within the multichannel single-phase model, what is the probability of zero customers in the system?

If the arrival rate of customers entering into a system is 3 per hour (assume Poisson Distribution), the service rate is 8 per hour (assume exponential distribution) and there are 3 channels operating within the multichannel single-phase model, what is the probability of zero customers in the system?