Permutations With Repetition and Restrictions

Hey guys, its me Gagandeep Malhans. Today Mr. Piatek taught us some examples on Permutations with Restrictions and Repetitions.

Let's look at some examples here as follows:

Example 1: Consider the word CALCULUS.

How many distinguishable permutations can be made from the letters in CALCULUS?

We can arrange C in 2! ways, the L in 2! ways and the U in 2! way.

 (8!,2!2!2!) = 7! = 5040 ways

Example 2: Consider the five digits:  31232

How many different numbers can be formed using these digits?

We can arrange 3 in 2! ways and the 2 in 2! ways.

 (5!,2!2!) = 30 different numbers 

Here is a video of permutations with repetition and restrictions

http://www.youtube.com/watch?v=0crbJNFoMII

I hope you gain something!   :)