Five individuals from an animal population thought to be near
extinction in a certain region have been caught, tagged, and
released to mix into the population. After they have had an
opportunity to mix, a random sample of 10 of these animals is
selected. Let X=the number of tagged animals in the second sample.
If there are actually 25 animals of this type in the region, what
is the probability that:
a) X=2?
b) X<=2?