Cars pass an intersection according to a Poisson process with rate. There are 4 types of cars, and cach passing car is, independently, type i withprobability pi,"=p= 1. 1. Find the probability that at least one of each of car types 1,2.3 but none oftype 4 have passed by time t. 2.Given that cxactly 6 cars of type 1 or 2 passed by time t, fnd the probabilitythat 4 of them were type 1.