Problem: At a dance party a group of boys and girls exchange dances as follows: one boy dances with girls, a second boy dances with girls, and so on, the last boy dancing with all the girls. If b represents the number of boys and g , the number of girls, then:
Answer Choices:
A.
B.
C.
D.
E. It is impossi- ble to determine a relation between and without knowing the total number of boys and girls.
Solution:
Set up the following table, a one-to-one cuirespondence between the elements of the boy set and the girl set:
therefore ;