Expert: Sherry Wallin - 7/6/2011

Question
I've tried to solve this problem but I can't. Please help me.

*How many mixed double tennis teams can be formed from 10 players, where 6 are male and 4 are female?

Answer
Hi John~

This is just a multiplication principal counting problem. If there are m1 ways to choose something and m2 ways to  choose another, then together there are m1*m2 ways or 6 * 4 = 24

Another way to think this out is to 'pretend' that the 6 males are numbered 1,2,...,6 and the females numbered as 7,8,9,10 and look at all possible ordered pairs:

(1, 7 ),(1, 8),(1, 9),(1, 10); (2, 7 ),(2,8),(2,9),(2,10);(3,7),(3,8),(3,9),(3,10);...;(6,7),(6,8),(6,9),(6,10)

It should be clear that there are 4*6 = 24 different mixed double teams

Math Prof