Hello I have a question about probability problem.

Problem B: Failures of a testing instrument from contamination particles on the product follow a Poisson process with a mean of 0.38 failures per an 8-hour shift. a) Find the probability that the instrument does not fail during a shift. b) Find the probability that there are more than 3 failures in a 48-hour period. c) Provided there is at least one failure in a 24-hour period, what is the probability that there are no more than 3 failures during that period