At a certain hot dog stand, during the working day, the number of people who arrive to

Question:

At a certain hot dog stand, during the working day, the number of people who arrive to eat is Poisson, with an average of 1 person every 2 minutes.
a. What is the probability that exactly 3 people arrive during the next 10 minutes?
b. What is the probability that nobody arrives during the next 10 minutes?
c. What is the probability that at least 3 people arrive during the next 10 minutes?