Suppose that the a class of students is star-gazing on top of the local mathematics

Exercise 4.15. Suppose that the a class of students is star-gazing on top of the local mathematics building from the hours of 11pm through 3am. Suppose further that meteors arrive (i.e. they are seen) according to a Poisson process with intensity A =4 per hour. Find the following: (a) The probability that the students see more than 2 meteors in the first hour. (b) The probability they see zero meteors in the first hour, but at least 10 meteors in the final three hours (midnight - 3am). (c) Given that there were 13 meteors seen all night, what is the probability there were no meteors seen in the first hour