Hi I have a question that has to be answered and I am not sure how to get the answer can someone help me please

A company receives 0.4 calls per minute from customers to register complaints about products
purchased from the company. Assuming that (I) the probability that a phone call is received in a given
1-minute period is the same for all the other 1-minute periods, (ii) the number of phone calls received
in a given 1-minute period is independent of the number of phone calls received in any other 1-minute
periods. What is the probability that during a 1-minute period
a. Two or three calls received?
b. Three or more phone calls will be received?

Thanks so much for your help