COMBINATION

What is Combination?

A combination is an arrangement of objects (numbers, letters, words, etc...) where order doesn't matter for example: 1, 2  is the same as 2, 1.

Formula:

EXAMPLE:

Evaluate 7c2:

7c2 = 7!/2!(7 - 2)! = 7*6*5*4*3*2*1 / 2*1 (5*4*3*2*1) = 7*6 / 2 * 1 = 42 / 2 = 21 (Answer)

There are 12 boys and 14 girls in Mrs. Schultzkie 's math class. Find the number of ways Mrs. Schultzkie can select a team of 3 students from the class of to work on a group project. The team is to consist of 1 girl and 2 boys.

             Order , or position, is not important. Using the multiplication continuing principle

                          12 C 2 (BOYS) * 14 C 1 (GIRLS) 12 * 11 / 2 * 1 * * 14 / 1 = 66 * 14 = 924

VIDEO

REFERENCES

(http://www.800score.com/content/gre/nCr1.gif)
(https://www.youtube.com/results?search_query=combination+in+mathematics)