Two friends operate a barber shop. The shop has two chairs where they can serve customers separately. There is also an extra chair where another customer can wait. The waiting customer is served by the first barber to be free. Arriving customers finding 3 customers in shop, leave immediately. Suppose customers arrive according to poisson process at a rate of 8/hr. Service time is exponentially distributed with mean 15 min. Find the steady-state probability distributions.