Chapter 7 Permutations and Combinations

NCERT Solutions for class 11 Maths Chapter 7 Permutations and Combinations

This page consists of NCERT Solutions for class 11 Maths Chapter 7 Permutations and Combinations prepared by HT experts. All the questions asked in Chapter 7 Permutations and Combinations are solved with detailed explanations. MCQ questions of Chapter 7 Permutations and Combinations are covered in this solution. 

What will you learn in Chapter 7 Permutations and Combinations?

Here, in this Chapter, we will learn some basic counting techniques without actually counting. In fact, these techniques will be useful in determining the number of different ways of arranging and selecting objects without actually listing them. The basic techniques of counting are : 

1 The two fundamental principles of counting (Multiplication and Addition).

2 Factorial notation.

3 Arrangements when all the objects are different.

4 The number of permutations of n different things, taken r at a time, where repetition is allowed, is n^r.

5 The number of permutations of n different things taken r at a time, where repetition is not allowed, is denoted by nPr.

6 Derivation and use of the formula of nPr.

7 The number of permutations of n different objects taken r at a time, where repetition is allowed.

8 Arrangements when all the objects are not different.

9 The number of selections of n different things taken r at a time is denoted by nCr.

10 Derivation and use of formula of nCr.

11 nCr = nCn-r

12 nCr + nCr-1 = n+1Cr

Now based on the type of objects we will be understanding the techniques to count the number of ways of selecting and arranging the objects.

Grouping and distribution are the two applications of selections and arrangements which we will understand in this chapter.

And then Circular permutations, De-arrangement and Multinomial Theorems will be the attractions of this chapter.

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