Let S be a set. If |{A ⊆ S | |A| = 2}| = 67, what is the cardinality of S?
Consider the binomial expansion of (2x - y)^16. Use the binomial theorem to determine the coefficient of the x^11y^1 term.
Suppose a, b ∈ Z⺠and the binomial expansion of (ax + by)^ab contains the monomial term 256xy^3. Use the binomial theorem to determine the values of a and b.
How many seats in a large auditorium would have to be occupied to guarantee that at least three people seated have the same first and last initials? Assume all people have exactly one first initial and exactly one last initial. Justify your answer.