2004 AMC 10A Problems/Problem 13
Problem
At a party, each man danced with exactly three women and each woman danced with exactly two men. Twelve men attended the party. How many women attended the party?
Solution
If each man danced with 3 women, then there were a total of pairs of a man and a women. However, each women only danced with 2 men, so there must have been
women
.