Permutation
A permutation is an ordered arrangement of the objects in a collection. They are further classified into two types. Repetition of Objects: - When a thing has n different types ….. !n Choosing r of something that has n different types, n * ....................... (r time) Example 1 : - In the lock, there are 10 numbers to choose from 0-9 and we choose 3 of them, 10 * 10 * 10 = 1000 (n**r) Example 2 : - How many 3 digits even numbers can be formed from the digits 1, 2, 3, 4, 5, 6 if the digits can be repeated? Number of 3 digit even number = 6 * 6 * 3 = 180 Without Repetition of Object: - In this case, we have to reduce the number of available choices each time. Example 3 : - In how many ways can a letter of the word PERMUTATIONS be arranged if the: - Words with start with P and ending with S let the first position be P & last position be S (both are fixed) Since letters are repeating. Total number of letters (n) = 10 & since, 2T Vowels are all together, Vowels in word PERMUT...