This is your question number 2 for today, out of 5 allowed.
Here's your question for category 'Probability-and-statistics'.
16 teams decided to participate in a football competition. In the preliminary round, the 16 teams will br divided into 4 groups and they have to compete with each other within group. The winner of the group will proceed to the semifinal.
Find the number of ways to form the 4 groups.
(Answer: 63063000)
C(16,4) = 16! / [ (16-4)!(4!) ]
=16*15*14*13/(4*3*2)
= 4 * 5 * 7 * 13
= 1280
Oh well