Hey bobbyb.
What do you mean by 10% arriving? This is an ambiguous statement since you already have a PDF. You will need to look at P(X = 10).
Here is the question:
Arrivals at starbucks in the concourse can be modelled by a poisson distribution with a mean rate of 5 per minute starting 10 minutes before class starts. What is the probability that 10% students arrive in the last minute?
HELP