Basics of Permutation and Combination

It is meant for class 11 students. But students of classes 9 and 10 will also be able to understand the concepts. I will cover: the factorial notation, the fundamental principle of counting and how to solve related sums. To understand the concepts, only concepts of arithmetic are required. Understanding the concepts of permutation and combination and solving related problems are essential for doing problems of probability. This chapter is very useful to enhance logical reasoning, as the problems can not be solved by merely memorizing the formulas. Permutation means arrangement. Different concepts in permutation help us find the number of ways some (identical or different) objects can be arranged. The arrangement could be with or without restrictions. Example: How many ways 5 boys can be seated in a row of 8 chairs. In combination, we find how many ways some objects can be selected from a larger pool of objects. Here, unlike permutation, the order in which the objects are being selected is ignored. Example: How many ways a team of 11 players can be formed from a squad of 15 players.