Algebra
posted by Pomi on .
In a certain soccer league, each of the five teams plays every other team in the league exactly three times each season. How many games are played in total in one season?
a) 15
b) 24
c)30
d)60
e)120

how many combinations of five taken 2 at a time?
C(5,2) = 5!/2!(3!) = 10
so 30