Question

Permutations, probability tutorial.

Answer 1

Lets start off with combinatorics.

Techniques for avoiding counting.

You have six shirts and four jeans. In how many shirt and jeans combinations are possible, discounting fashion.


Instead of counting, we can multiply and get the same result. 6 x 4 = 24.

In addition to the six shirts and four jeans you also have three hats. How many different outfits are possible, discounting fashion of coarse.

Instead of having to draw and count we can take this "short cut" again.

6 x 4 x 3 = 72

The fundamental counting principle:
If one task can be done in m ways, and another task can be done in n ways, then both together can be done in m x n ways.