Name:
Directions: Show all work. Unless otherwise directed, you may leave your answer in terms of factorials,
falling factorials, and binomial/multinomial coefficients. Any sums or products should be as simple as
possible.
- [2.5 points] How many -element
subsets of
are there? Give an explicit numerical answer.
- [2.5 points] A group of
people must be split into two teams of size
and five teams of size .
How many ways can this be done?
- [2.5 points] A random lattice path of length
is generated by starting from .
At each step, we increase the -component
by
with probability
and we increase the -component
by
with probability .
What is the probability the lattice path ends at ?
- [2.5 points] A standard deck of cards has one card for each of the suit/rank pairs. The suits
are spades, hearts, diamonds, and clubs; the ranks are ace,
through ,
jack, queen, and king. What is the probability that a poker hand (i.e. a set of
cards) has at most
cards in each suit?