discrete probability question?

Question

a resource centre has 4 copies of a particular film for rental over 1 week perod the demand by borrowers per week is a poisson distribution with mean 3
A) find the expected number of copies that will be rented out in a week

Answer 1

In general, if X has the Poisson distribution with a rate of λ events in t time units then:

X ~ Poisson(λt)
P(X = x) = (λt)^x * exp(-λt) / x! for x = 0, 1, 2, 3, 4, ...
P(X = x) = 0 otherwise

the mean of the Poisson distribution is the parameter, λt
the variance of the Poisson distribution is the parameter, λt

in this question the parameter is 3 and so the mean and the variance is 3.

Answer 2

Am I missing something here? A mean of 3/week means that the expected number is 3/week.