# RS Aggarwal Class 11 Chapter 9 Solutions (Combinations)

RS Aggarwal Solutions for Class 11 Maths Chapter 9 – Combinations will give you proper guidance about the chapter. These solutions are created by our best team of maths experts so that you can get 100% error-free and high-quality solutions without any problems. Chapter 9 of RS Aggarwal Maths book is based on an interesting concept of combinations which will help you score more marks in your CBSE exams.

This chapter has around 4 exercises with approximately 60 questions. All the questions are based on the latest CBSE exam pattern. The questions range from basic numerical to difficult questions that you may not be able to answer properly. The Instasolv team is always there to provide you with RS Aggarwal solutions to all the questions. The solutions designed by our experts are result-oriented. All of your worries associated with the chapter will fly within minutes as we dedicatedly work to give you the best assistance.

## Important Topics of RS Aggarwal Solutions for Class 11 Maths Chapter 9

In Chapter 9 of RS Aggarwal Book for Class 11, you will study concepts like the definition of combinations, the difference between permutation and combination, how to solve questions using combinations property, solving questions using combinations formula and how to solve questions with both permutation and combinations.

**Combination**

Combination refers to the way in which you can calculate the total outcomes of an event where the order of outcomes at the end does not matter. You can easily find the total outcomes using the formula:

nCr = n! / r! * (n – r)!,

‘N’ here denotes the total number of items and ‘r’ represents the total number of items that you choose at a time.

**Difference Between A Permutation And A Combination**

Ordering is the main difference between permutations and combinations. In the case of permutations, you need to care about the order of elements, whereas in the case of combinations, you do not need to care about the order of elements.

Generally, you can use the word *arrangements *for permutation and the word *selection *for combinations.

**EXAMPLE 4**

(i) AB and BA are two different permutations but each represents the same combination.

(ii) ABC, ACB, BAC, BCA, CAB, CBA are six different permutations but each represents the same combination, namely ABC.

**Important Results on Combination **

- The number of combinations of n different things taken r at a time allowing repetitions is
^{n+r-1}C_{r}

- The number of ways of dividing n identical things among r persons such that each one gets at least one is
^{n-1}C_{r-1}

### Exercise Wise Discussion of RS Aggarwal Solutions for Class 11 Maths Chapter 9 – Combinations

**Exercise 9A**

This exercise 9A has 14 questions in which you need to find the value of r.

**Exercise 9B**

In exercise 9B there are around 26 questions in which you have to find a number of ways in different situations.

**Exercise 9C**

This exercise 9C has 5 questions in which you need to find the number of ways in which a situation can be created.

**Exercise 9D**

In exercise 9D, there are around 18 questions. This exercise is a combination of different topics of the chapter in which you need to find the value of n or finding the ways in which a situation can occur.

### Benefits of RS Aggarwal Solutions for Class 11 Maths Chapter 9 – Combinations by Instasolv

Instasolv is an online learning platform where all of your doubts are solved easily. The team has proficient experts who work day and night to give you the best solutions to all the tough math questions. All the questions in RS Aggarwal Class 11 Maths Solutions Chapter 8 are designed according to the latest CBSE exam pattern. If you understand all the concepts of the chapter properly, then you can easily solve the questions of the book. If not, Instasolv is always there to provide you with the best solutions to all the questions. Our team makes even a difficult chapter easy for you.