2014 Guts #20: Odd Number of Ranks
Source:
April 21, 2014
Problem Statement
A deck of cards has ranks numbered –. Each rank has four suits - hearts, diamonds, clubs, and spades. Each card has a rank and a suit, and no two cards have the same rank and the same suit. How many subsets of the set of cards in this deck have cards from an odd number of distinct ranks?