please help with numbers 1 and 2!

lework 3 will be based on the concepts of this homework. The number of customers arriving at a grocery store can be modeled by a Poisson process wi intensity ) = 20 customers per hour. (a) Find the probability that there are 5 customers between 9:00 and 9:30. (b) Find the probability that there are 6 customers between 9:00 and 9:20 and 8 customers bety 9:20 and 10:00. Assume the number of rainfalls in October in Clarksville forms a Poisson process with 1 rainfall e four days in average. (a) Find the probability of 3 rainfalls by day five and 6 rainfalls by day twelve, and (b) Find the probability of at most 2 rainfalls by day five and at least 3 rainfalls by day eigh bility th