How to use this applet:

The total number of boys in the class is entered in the first input box.
The total amount of girls in the class is entered in the second input box.
To specify the number of boys wanted on a team you click on the picture of the boy
The counter beside the picture of the boy should count upwards with each click
Repeat the process for the number of girls wanted on the team
Click on the Answer button and the applet will calculate the answer

Notes on the maths used in the applet:

This Applet explains the concept of nCr (n Choose r). This finds the number of ways a set of r elements can be picked from a set of n elements.

The formula used is: nCr = (n)! / (r!)(n-r)!
where: / = divided by

This Applet uses the concept of a class of boys and girls. Since there are two seperate sets (Boys and Girls) firstly we work out nCr for the boys and then multiply it by nCr for the girls.

Example: If we have a class of 5 boys and 5 girls and we want a team of 2 boys and 3 girls we calculate 5C2 and multiply it by 5C3. In this case the answer is 100. This means there are 100 different possible teams consisting of 3girls and 2 boys that can be picked from a class of 5 boys and 5 girls.