Arrivals of the Number 1 bus form a Poisson process with rate one bus per hour, and arrivals of Number 7 bus form an independent Poisson process of rate seven buses per hour(a) What is the probability that exactly three buses pass by in one hour?(b) What is the probability that exactly three Number 7 buses pass by while I am waitingfor a Number 1 bus(c) When the maintenance depot half the buses break down before they reach my stop. What , then is the that i wait for without seeing a single bus?