Question

If there are 5 teams in one league and 6 teams in another league and if each team from one league plays one team from the other league once how many games are played?

Answer 1

visualize the first set of teams as
a b c d e
and the second set of teams as
1 2 3 4 5 6

so we have
a1 a2 a3 a4 a5 a6
b1 b2................b6
....
e1 .....................e6

that would be 30 games

or

we have to choose one from each group
number of games = C(5,1) * C(6,1) = 5*6 = 30