Basics of Permutation & Combination For SSC & Bank Exams

 

Permutation and Combination MCQ are commonly asked in Bank and SSC exams. So, candidates must understand specific permutation and combination tricks and hacks to solve these sums accurately and quickly. Before we learn to solve permutation and combination sums, we need to first understand what factorial is :

Factorial

The factorial of a number is a product of the number starting from 1 up to that number. Let us consider that the number is “n.” Thus n ! can be defined as =1*2*3*4*5*6*7*8*9 ………x(n-2)x(n-1)xn. 

1! = 1

2! = 1*2 = 2

3! = 1*2*3 = 6

4! = 1*2*3*4 =24

5! = 1*2*3*4*5 = 120

Here are two tips related to factorial = 

 0! = 1

1! = 1 

And

We cannot find the factorial of any negative natural number. 

Factorials are mainly used to find the arrangement of any numbers. Factorial forms the basis of permutation and combination. Thus we have to learn how to solve the factorials if we want to apply that same concept to solve permutation and combination problems. 

Permutation and Combination Aptitude Tricks and Formulas 

Suppose there are total “r” things that have to be arranged. The permutation formula says that it can be done in nPr ways. 

Combination formula = nCr = n! / ((n – r)! r!) n = the number of items.

When we are talking about both permutation and combination, there is one more trick that you must know. If any particular thing can be done in ‘m’ number of ways and another thing can be done in ‘n’ particular ways, then the total number of ways in which either of them can be done is m+n, and the total number of ways in which both can be done is m*n. This is a super helpful hack that helps solve many questions in the exam.

Permutation and Combination MCQ Samples

1. A closed box has five yellow, four green, and three white balls. A person draws out any three balls randomly. Find out the total number of ways the three balls of different colors can be drawn out.

2. How many different ways can a programmer choose five computer courses if there are a total of 9 courses and 2 of them are mandatory for all?

3. How many diagonals can be present in a decagon?

4. How many different words can you form by using all the letters of the word  “EDUCATION.”

5. Seven children are to be assigned seats on a bench. How many different ways can you make them sit if the youngest child is always made to sit in the bench’s middle?

6. There is a polygon of 14 sides. Using all the vertices of that polygon, how many triangles can you draw?

7. There are totally 7 fans in a room. Each one of them can be turned on independently. Find the total number of ways in which you can ventilate the room. 

Hacks to Solve Permutation and Combination Problems

Here are some tricks and hacks for Permutation and Combination Problems: 

• Enhance your speed: This is the first trick. Permutation and combination problems are not lengthy, and they do not need much time to solve. Thus your first target should be to solve these questions as soon as possible.

• Understand the type: Permutation and Combination problems have a few specific genres of questions that are mostly asked in the exam. As you practice more, you get to explore different types of questions. Once you can identify the type, it will get easier.

• Read the question: The language for these questions is always tricky. You must read the questions many times to understand the true meaning and answer it accurately. 

Why Do You Need Coaching For Competitive Exams?

Competitive examinations for job recruitments, such as SSC or Bank IBPO exams, are excellent opportunities for candidates to enter into service within the public service domain. Thus, many aspirants appear for these exams every year. However, solid preparation is needed to score well in these exams and get into a good position as per merit. 

This preparation journey becomes more straightforward, smoother, and hassle-free when backed by reputed guidance. Coaching for competitive exams can help you assess your performance level, track your progress and thus get better at scoring well during the exams. These coaching classes will provide well-researched permutation and combination notes that will help you in your preparation. Such institutes will also provide you with permutation and combination practice questions that you can regularly practise. So, enroll yourself in the best coaching today to ensure success in competitive exams.