COMBINATROICS: Factorial GRE QUANTS SRIJITA BANERJEE https://unacademy.com/user/mampi

Factorial Represented by"I" Factorial of n n! Product of the consecutive smaller number including that number 5! 5*4*3*2*1 02

What GRE wants . 10!> 1 million (1046) 13!> 1 billion (1049) 15/> 1 trillion (10 2) Recognizing factors of high factorials For example: 20! 20 19 18 20. = 20*191 = 20*19*181 = 20*19*18* 17! 02

When we are only concerned with the element selected and the order doesn't matter or come into picture

A group of 12 people are there in a classroom. How many handshakes are possible if each person shakes hand once with each other person in the room? 02

A group of 12 people are there in a classroom. How many handshakes are possible if each person shakes hand once with each other person in the room? There are 12 people in the roonm. 02

A group of 12 people are there in a classroom. How many handshakes are possible if each person shakes hand once with each other person in the room? There are 12 people in the room. One of the 12 people, shakes hand with 11 other people. 02

A group of 12 people are there in a classroom. How many handshakes are possible if each person shakes hand once with each other person in the room? There are 12 people in the room. One of the 12 people, shakes hand with 11 other people. Now, if we do not consider the repetitions, then the number should actually be 02

A group of 12 people are there in a classroom. How many handshakes are possible if each person shakes hand once with each other person in the room? There are 12 people in the room. One of the 12 people, shakes hand with 11 other people. Now, if we do not consider the repetitions, then the number should actually be 12*11 02

A group of 12 people are there in a classroom. How many handshakes are possible if each person shakes hand once with each other person in the room? There are 12 people in the roomm One of the 12 people, shakes hand with 11 other people Now, if we do not consider the repetitions, then the number should actually be 12*11 But this includes A shaking hands with B and B shaking hands with A. Which is ultimately the same and that is what we do not want, So basically it is getting doubled 02

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Srijita Banerjee

B.Tech in Biotechnology\singer\loves teaching\public speaker\peer educator\Bengali

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Mahendra KUMAR

7 months ago

thanks mam very nice teaching way
mam aap konsi books follow karti hai plz batana

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Suman Lata

7 months ago

Thanks for your feedback, mere lesson kai book or notes se taryar h