true

Take Engineering Entrance Coaching from the Best Tutors

Affordable fees
1-1 or Group class
Flexible Timings
Verified Tutors

Search in

Derangements, Arrangement Of Things So That No Elements Appear In Their Original Place (Important for IITJEE)

Sujoy Das

31/01/2018 3 0

"Like if I have 5 tshirts and i want to gift them to my 5 cousins named A,B,C,D,E, so find number of ways in which particular cousin won't get their particular tshirts."

So number of ways:

D(n)=n!(1-1/1!+1/2!-1/3!+.....(-1)^n1/n!))

Where n is number of things which don't go to their original position
here in this question n = 5

So 5!*(1-1/1!+1/2!-1/3!+1/4!-1/5)) = 44 ways in which 5 tshirts won't go to their original position

D(1) = 0

D(2) = 1

D(3) = 2

D(4) = 9

D(5) = 44

D(6) = 265 (( remember these values of Dearangements )).

3 Like 0 Dislike

Follow 5

Other Lessons for You

Ways to Learn Faster, Deeper, and Better Recall Techniques

Listen to music. Researchers have long shown that certain types of music are a great “key” for recalling memories. Information learned while listening to a particular song or collection can...

Pawan Rama Mali

6 2

How To Write A Dimensional Formula? (Class 11)

In order to make the measurement of a physical quantity we have, first of all, to evolve a standard for that measurement so that different measurements of same physical quantity can be expressed relative...

Mahesh Kumar

1 1

Fastest way How to check if a number is a Perfect Square or not

Squares of all integers are known as perfect squares. In this lesson, we will discuss a very interesting Mathematical shortcut: How to check whether a number is a perfect square or not. There are some...

Debraj Paul

5 0

Java 9 , the new beginning

Java 9 is here! A major feature release in the Java Platform Standard Edition is Java 9 Lets see what more it offers more than its previous versions Java platform module JEP 223 : New version...

GCC

0 0

Polynomials {Class-10 / CBSE}

Polynomial - ConceptA polynomial is a mathematical expression consisting of the sum of terms, each term including a variable or variables raised to a power and multiplied by a coefficient. Zeroes of a...

Optimize Tutorials

2 0

Find Engineering Entrance Coaching classes near you

Online Engineering Courses

Looking for Engineering Entrance Coaching classes?

Learn from Best Tutors on UrbanPro.

Are you a Tutor or Training Institute?

Join UrbanPro Today to find students near you

Engineering Entrance Coaching Questions

For physics, is HC Verma good?

6 Answers

What is the best way to master physics?

5 Answers

How do I clear concepts of physics?