Permutations

[@gwiough1656]

In behalf of all the people cramming for their finals right now, thank you!

[@Clammychow]

And here I am, three years later. My final's tomorrow XD

[@avory7938]

@@Clammychow and here I am, 3 years later. My final's tomorrow xD

[@radd4255]

@@avory7938 Here I am, a year later. My final is tomorrow.

[@yamboyasmr4779]

@@radd4255 I'm here a month later finals tmr

[@ivanmartincampoy]

@@yamboyasmr4779 i'm here a month later as well

[@ガジュマル-s1f]

My statistics professor is someone who explains things for people who already know about the topic. There are variables everywhere which are not explained. Thank you for making this video, it showed me how simple this actually is and how fun the topic can be.

[@EricaMorgan]

Whhhhhyyyy doesn't my genetics professor teach it this way??? the formula is so confusing, but the way you explained it I understood it and it's so easy!

[@socaljusticewarrior558]

Because your genetics teacher isn't an attractive math man

[@esperar1]

This is currently the clearest video I've found on permutations. It actually explains the concept behind the equation, which will stay in my understanding far beyond the memory of the equation. Thanks!

[@Tosserke]

I use these videos for my exams at university, just love this. It's no drama if I skip a class, this is taught even better

[@maitrigandhi51]

This is so EASY. I have an exam tomorrow and I'm relying on this video for 5 marks! Extremely helpful!!

[@clockfixer5049]

Maitri Gandhi how it went?

[@shekelboi]

For others viewing the video: at 8:00 please note that the factorial symbol should be outside the parenthesis: n!/(n-k)!

[@acatindisguise]

you explained it better than the lecturer at school. thanks for this video :)

[@adamdintelman2067]

Holy shit, this guy does everything! I mean seriously, what can'd he do?

[@dboijahskush1251]

hes a alien here to help us not destroy ourselves

[@ashpbrrrr]

darius jah'skush ALL HAIL THE ALIEN WHOSE VEEN SAVING OUR GRADES!!!

[@amanrubey]

he's an mitian

[@atriyakhan8535]

Adam Dintelman ikr!

[@suneelnadipalli2685]

Teach badly

[@TechLord79]

Thank you very much, when I learned that at school back then they went over it too fast and I could not get the reasoning behind the formulas. I see clearly now, well presented :-)

[@seemade4432]

In India permutations is taught in class 11 & 12 but due to this awesome guy I understood the topic even after being in class 9 . Thanks Sal

[@shashankpandey1966]

are you in state board ?

[@Swiizzey]

7:58 I feel bad for people watching this on mobile and not being able to see the annotation correction and get really confused

[@eliaskountouris4214]

Swiizzey what I'm on mobile pls help

[@jugsmcflugs4954]

Elias kountouris equation is supposed to be n!/(n-k)!

[@advaitpai1615]

DeformedBear who the hell allows phones into examination halls

[@suneelnadipalli2685]

Sal wrote n!/(n-k!) It's supposed to be n!/(n-k)!

[@troyawaneedavisd]

Swiizzey And I certainly did get confused!! Thumbs down for me!!

[@aerismagia8058]

I would like to see Sal teach electrical engineering.

[@thelamp091]

It is a video from many years before bir it's still very helpul. Thank you so much!

[@levizraelit5557]

Thank you so much. I've spent an entire day trying to understand this from the textbook with no success.

[@moneychica]

THANKS! These are great tutorials, I'm currently doing online schooling and my cousin just recommended you.

[@farenkofi]

I am very grateful for the explanation and logical reasoning. The basic concept is what i really needed and that it something i didn't have while doing additional math for IGCSE. I'm happy nonetheless I have understood in A level statistics. Thank you.

[@ronroyes2375]

I usually don't understand his vids, but he taught this so easily... even I could grasp the concept this time 😅

[@balsyitlog]

Thank you khan for always bringing me one step closer to smartness.

[@heldan898]

3 balls, 2 cups

[@aaaasssskkk11111]

THANK YOU THANK YOU THANK YOU!!!!! I have a probability test next peroid, and didn't get it until I watched this!!!!!

[@sureshchaudhari4465]

Hi I was very weak in maths I wish internet was super cheap in my academic years I would have got better marks and understanding about maths concepts.Thanks Khan Academy

[@LAnonHubbard]

Good explanation. I've always found this sort of thing confusing but this video was very clear. Great intuition gained.

[@rahafhesham3262]

me in 2020 tryna understand this topic cause online school doesn't help

[@legendinbusiness2022]

Thanx khan academy for making the impossible possible coz i am just studying in9th standard and i need to write an olympiad based on 16 chapters which includes combinations and permutations. And now may be i will achieve a good rank in it.

[@AishLovesSpaghetti]

You explained everything very cleary using easy practical examples. Keep up the good work!

[@Death_User666]

i am in college and i am learning this all on my own thanks to this guy

[@ThomasMendenhall]

You are the reason I survived 6th grade. thanks for making these videos.

[@aditishikha8149]

Great work sir. Thanks for making me understand this thing so easily.

[@mariapineyrua5405]

you are the best! i been using your videos since I was in remedial at college, know I'm in my last year of the university. doing qmb. you should be a professor! thanks

[@scoldingMime]

"And I want to know, how many different ways can I put these 3 balls into these 2 cups?" Call me immature, but I started chuckling. Aside from that, this was very informative.

[@samanthamanego2923]

Been sitting in a chair for 2 hours, but I've never understood it. Now, 10 minutes and I have understood at least a tinsy bit.

[@jugsmcflugs4954]

I learn more from this than my geometry teacher

[@abdullaprobably]

Wow this style of teaching is soo good

[@dennisphieros7266]

Khan Academy rules...

[@anshikakushwaha3150]

2018!? Time flies fast. 2008 passed 10 years back!

[@nocturnalvisionmusic]

Now August 2022 😌🥳

[@nocturnalvisionmusic]

Now end of November 2023. 😌🙏

[@ozzyfromspace]

Wig snatched. Thanks Sal, I needed this refresher (found an application for it in my research so many years later lol).

[@const71]

great explanation ... a good analogy might be scrabble tiles on the rack played on the board squares...

[@Littlechonch]

Oh my god thank you so much our teacher has literally taught us nothing about this and has told us to research it for our assignment this helped so much

[@ucHorrible]

Mine did, too! It was the last lesson in the chapter, too xD

[@ucHorrible]

***** 8

[@Littlechonch]

HermitOfTheFragshack Oh you poor soul I'm in grade 10

[@Diegoangola1]

+HermitOfTheFragshack me too

[@Diegoangola1]

Thank You, actually i had a Pre-Algebra book and i couldnt understand it, but with the video i could

[@Mslokalove]

You're a life saver!!❤❤❤

[@abhishekravindra4008]

I got intuitive blast after watching this it made so much sense looking at the angle from that you want the first k terms of the n! Then its almost common sense that you want to cancel out the left terms so you are doing (n-k)! To cancel them (n-k) is number left from n after occupying n spots

[@madhuc52]

I look at this in a much simpler way as below " 3 chairs and 7 people" First spot could be fitted in 7 different way or people in this case. For this 7 different ways of first position there will be 6 different way remaining 6 people can occupy hence 7*6 ways two chair get filled, now again third chair has 5 left over people from each outcome (7*6 total outcomes ). So these 5 will occupy in 5 different way with total outcome of first two chair i.e (7*6)*5. If one more chair is there again we have 4 different ways remaing 4 can be associated with this all possible outcome. By THE WAY mathes is too difficult to explain or visualise through words. Happy learning.

[@grand_tp]

At 7:55 , it is n!÷(n-k)!

[@logicool2793]

Гленн Борс you sir are correct. please note everyone. it is NOT n!/(n-k!)

[@rtoriq]

i'm with you 100%, bc it irritates me how NO ONE, not even textbooks explain how you just up and multiply. The reason you multiply is just think of what multiplication represents: groups. 7x6 means 7 groups of 6 (or 6 groups of 7). That gives you 42, either way. 3 groups of 2 (or 2 groups of 3) give you 6. Well, if you have say, 4 balls (A, B, C, D) and 3 cups, for your FIRST choice of A, there's 6 ways -6 groups of choices- to fill the 3 cups IF you're starting your choice with A....

[@farouku5334]

old but gold

[@valsastephen9054]

Reason for multiplying eg you want to go from A --B--C,with three possible routes to B and from B 4 ways to C.for every route to b there are 4 ways to C.total =3*4=12 ways for A to C

[@somber_soul]

@moka22051 A factorial is when you multiply that number by all the positive integers below it. For example, 7! is 7*6*5*4*3*2*1.

[@IGzzyderWhizzy]

There are 7 ways of selecting the first person to sit, and FOR EACH way out of the 7 ways, there are 6 ways of selecting the second person. Thus far there 7 * 6 ( = 42) ways of selecting the first two persons and sitting them. Again FOR EACH of the 42 possible ways of selecting the first two persons, there are 5 choices for the third sitter. Eventually we have 42 * 5 ways of selecting 3 out of 7 persons to sit.

[@pzsmcrew]

THANK YOU REALLY MUCH, I have tomorow big math exam, it helped me a lot

[@lastnamefirstname8954]

So , how was the exam?

[@1337w0n]

Its a drawing pad. You'll also need screen recording software, video editing software, and voice recording software. And a mike. I'm not sure if that software should come with either the mike or the pad.

[@axelthefuccboi764]

I'm doing this in 7th grade SOO... This is REALLY helpful

[@Ryoroyzu]

@jarrasoma Well, given i.e. 5 cups and 3 balls - and you put one ball in one cup - you'd have this; Cup 1: Ball A Cup 2: Ball B Cup 3: Ball C Cup 4: No ball Cup 5: No ball Now, there's a problem with our ascertion. Can you see it? The question now is better answered as a relation; In how many ways can you place a cup and a ball together? That way, the places would be the "k", and the other relation would represent the "n".

[@scaredyghosts]

I just found a link of his KZbin channel in my textbook...I mean I love videos so I got curious. And I don't regret I did that.

[@anandsivadoss]

Quality is a concern over here when you watch online. But if you download the same & watch it with VLC player, clarity is superb...:)

[@anjalidutta8471]

Hey, I think you should put that factorial sign of k outside the braces in 8:04

[@SuPeRm4n100]

idk how you know so much...thanks alot man!! :) really helped

[@amirisma7972]

the quality of the video is amazing

[@TheDailyCat101]

Thank You your videos are awesome for online school.

[@escodrumer]

Great video!! keep it up... better than my math teacher

[@satisfiction]

So in Braille there are 6 spaces... how many unique characters are there then? Because space 1 and space 2 being filled is the same as space 2 and space 1. Would it just be binary then? 2^6?

[@aal2002]

Thank you for making this so understandable!

[@bagitandbinit]

this video is such a great help, thank you

[@aimenwaseem7854]

omg thank you so much i might just pass my public exam with this (":

[@maddiericke1793]

Did it bother anyone else at the beginning of the video where he didn't have a whole line over the 2? Maybe it's just my OCD again...

[@chadfranklin47]

+Chill Edits lol

[@okcfan0217]

I didnt realize that until now. Thanks for making me annoyed

[@okcfan0217]

The bigger problem is the unclosed six at the left center

[@chhunchhim2546]

Yeah, It annoyed me for a sec. Then I realized, oh, he must be using a Windows XP machine. lol Man!! His videos has sure come a long way.

[@bhyll2489]

this guys lessons are awesome

[@TORAH4TEENS]

Yeah dey ma be techen stu nonsence

[@Technikplayzzz]

thanks Khan your vid's help so much ☺☺☺

[@frankthetank1285]

Thanks, your videos are always great!

[@malbagashi]

Thankyou sir I really respecte what you for us Teens and Kids

[@aminaharis4384]

You save my life thank you so much really

[@loverofbeats]

please do combinations with repetition! it would be greatly appreciated! :D

[@harshgog8212]

Thankss KA!! gosh ur the bestt!! i totally understand this now!!

[@medo5101]

Wonderful Explanation !

[@ZelForShort]

So if u have 7 traits, and 2 alleles/ possibilities for each trait. to calculate the possible combinations for 7 traits you would have 14 different​ traits/people. So your trying to seat 14 different people in 7 chairs/traits so? 14 x 13 x 12 x 11 x 10 x 9 x 8?

[@NoName-be8vp]

Dang but my teacher did it so different from you and she doesn’t even teach the class that well. So now I’m confused x 16

[@shishirdixit5996]

Out of 18 points in a plane, no three are in a straight line except 5 which are collinear. How many straight lines can be formed & how many triangles can be formed? Sir why do we need to subtract 5c3 from 18c3 in case of triangles

[@rianarang5207]

This helped me a lot!

[@cherrylouvillas6769]

I'm here in preparation for my licensure examination.😆

[@brianbernal8064]

Better than my math teacher

[@marianfrac1569]

how many 4-digit numbers can be formed from the digits 1,3,5,6,7,8 & 9 if no repetition is allowed? help pls

[@ehtishammashkoor8567]

7*6*5*4= 840

[@preciousjadegolveo6146]

Marian Frac 840

[@jermam2010]

What if you have just one chair and you can only fit like 4 people? Need help on this

[@atharvabaste4455]

hey sal, i'm not understanding this question (it's from iit exam)........ A train timetable must be compiled for various days of the week so that two trains twice a day depart for three days, one train daily for two days, and three trains once a day for two days. How many different timetables can be compiled?......plz answer or better make a video....

[@freeman5860]

an oldie but a goodie

[@shishirdixit5996]

A question paper had ten questions. Each question could only be answered as True (T) or False (F). Each candidate answered all the questions. Yet, no two candidates wrote the answers in an identical sequence. How many different sequences of answers are possible? Sir when it asks about sequences that means arrangements why can't we apply this formula 10 p 2 to find the answer ?

[@raees2046]

how many four digit no with diff digit can be formed if unit and thousands digit must be prime?

[@junkheadrooster]

oh thank you. real kind of u mr. old guy.

[@robertbutcher222]

In the first example with the 3 chairs why would we use npr? Npr is for when order manners. How does order manner here???

[@liliacfury]

The first person that makes sense.

[@mohitshresthanep]

Thanks for the subtitles, kid.

[@AnaRp1103]

Quick question: If I have to post 5 letters in 4 letter boxes then why is the no of possibilities equal to 4^5? why not 5P4?

[@just4anything]

1337wOn, what brand of drawing pad do you recommend. Thank you

[@ralpharances]

what do you mean by w/o restriction? example?

[@kokonnichiwa]

thank you, i understand more now.

[@itzoUSA]

Very well explained!

[@semityyy]

what about putting all the ball in one cup? is that not a possible scenario

[@saurabhs4743]

in how many ways can a bus with seating capacity of 5 carry 7 passengers?

[@tanutalwar7088]

Here in 2022, best lectures👍

[@gamerstormz67]

@ninjaturtle205 lol a brown ball n yello ball too and he puts them on the cups!

[@gwyneabundo5423]

This helped me allot!

[@khangle121]

How do you do it? What is this software?