Probability Trees (Dependent Combined Events) | Conditional Probability | Grade 5+ |GCSE Maths Tutor

[@laibanadeem7811]

I litterally just note down the lessons we do in lesson and come home and watch you video on it. Basically you are my gcse maths teacher sir GO ON SIR👍

[@Supply916]

Shush

[@laibanadeem7811]

@@Supply916 ARE YOU STUPID

[@Pwnage-ss3um]

@@Supply916 LOL

[@rayhaan7860]

@@Pwnage-ss3um haha

[@TomJ211]

Fr

[@KK-mk8xb]

best maths youtuber going🙌🏽

[@TheGCSEMathsTutor]

k sam Thanks a big statement! thank you so much! It’s really appreciated!! 🙏🏼

[@muhammadaizaz2233]

I can not disagree with u

[@username-sb1hp]

👆👆 for real

[@minecraftlovaaa]

best maths teacher on youtube thank you so much for everything

[@TheGCSEMathsTutor]

Thank you so much for the kind words! 😁🙏🏼

[@omarsangani3282]

fax

[@phliqqy5475]

luckly fella

[@MKhan-qe9lp]

9:29 and 17:08 exam practice.

[@cloudzyfn1496]

YOU are amazing when the teachers were explaining it at school i did not understand and when i watch your videos i understand Thank you so MUCH plus can you not simplify the answers

[@TheGCSEMathsTutor]

Thank you so much for the kind words I’m so glad to hear that! In regards to simplifying the answers, you can but you don’t gain extra marks! And if you simplify incorrectly you can lose marks.. so it’s a relatively pointless step to worry about! 😁🙏🏼

[@sbonganzimande6500]

Starting to think i might not need to go to school, i can just watch your videos 😅😅.Thank you so much

[@TheGCSEMathsTutor]

Haha if my videos are that powerful for you, imagine how good you’re going to be having both 😁💪🏼

[@Bruno4B]

Do you need to cancel down a probability fraction? Also, thank you for all your help.

[@TheGCSEMathsTutor]

No you can leave it as it is 😁🙏🏼🙏🏼

[@theblackswordsman3579]

This guy is saving my life

[@f.whyyouhere]

i feel like they need to show us your videos in school because they make so much more sense than my teacher

[@gemmakhan8419]

Great video. Just wondering why at 11:08 rr is 3/10. however in the question it says he takes two counters out at random. Is it me or is it just the way the question is worded

[@TheGCSEMathsTutor]

Gemma Khan The question is worded strangely, when it says “two counters are removed” it means that one is removed, checked and then a further counter is taken on the second pick. So hence on this tree only one counter is removed by the time we reach the second branch. This language always confuses students in exams!! 😁🙏🏼

[@gemmakhan8419]

@@TheGCSEMathsTutor oh that makes sense now. Thank you sir

[@aryamrege9829]

I have heard the formula P(A AND B) = P(A) * P(B) where A and B are independent events so why are we multiplying the probabilities when the events are dependent.

[@TheGCSEMathsTutor]

Aryam Rege We always multiply probabilities like these regardless of wether they are dependent/independent! For a more thorough description why it’s worth watching the video on the product rule for counting! 😁🙏🏼🙏🏼

[@Madni-pv1hv]

11.07 .. Sir can u explain how one number Dropped down when 2 countes were taken

[@readingamber]

thats what im confused ab..

[@yourlocalshortie4316]

​@@readingamber because they took them in 2 different "takes" So,like, : Person: takes one counter from the bag Same person: takes ANOTHER counter from the bag They took 2 marbles, but not at the same time

[@harjifs]

You must get so many views as people come to see your videos yearly

[@TheGCSEMathsTutor]

It takes a long time but it’s getting there 😁🙏🏼

[@hemanthsai6161]

@@TheGCSEMathsTutor i donot get it like hen u have mentioned cameron takes two random counters possibilites must be 5 right why 6?

[@As-iy2ki]

At 8:20 what if 3 counters were taken at random? Would we have to do 3 branches?

[@LolllaGigi]

Add another tree

[@As-iy2ki]

@@LolllaGigi I finished my A-Levels at this point. Been 2 years since I have done so but thx for the reply I guess lol. I forgot about that comment.

[@K4SP3R69]

You make more sense than my actual maths teacher

[@CarolynZele]

what video is the one you talk more about the terminology they use in these type of problems

[@idekkkkkk5647]

for the biscuit question, wouldn't it just be easier to work out probability of getting the same type of biscuit and then doing 1 - Ans ?

[@Mucha.offical]

YoU know the 2nd question shouldnt you take away 2 instead of 1 as he took 2 counters out?

[@TheGCSEMathsTutor]

SuperBob The first branch represents the first counter, the second set of branches represent the second counter that is taken, we can only use these trees to calculate one at a time, even though it says two are taken we are assuming this was one after another rather than reaching in and taking 2 at the same time! Hope this helps 😁🙏🏼

[@kawlanonya833]

i don't get it, does this mean that on the first branch he already took 1 counter?/ i get confused easily

[@kawlanonya833]

@@TheGCSEMathsTutor actually wait I think I know what your saying/ so it doesn't matter if they take 3 or 8 counters. we will only take one counter away?'

[@justsomeone5660]

thank you so much! this was quite helpful!

[@harriszahid2817]

You teach harder questions then other websites i applaud that but i wish you would supply more exams for 2020 gcse

[@TheGCSEMathsTutor]

Thank you 😁🙏🏼 All coming in good time!!

[@GamingWithJas-ff4yf]

As a set 1 i see people in the comments who find this harder than i do, and im the one thinking im bad at maths when it is easier for me to understand this at school then everyone else.😊

[@yousifalani3175]

Just like you to know this helped alot mate I appreciate your time for doing this

[@TosinOdetola-k7j]

Could this be on non calculator ?

[@minecraftlovaaa]

Why 3/6 at 8:10 for the third tree diagram? Isn’t it 2/6? why did you add one to 2/6

[@minecraftlovaaa]

Ohh never mind I got it

[@GCSEALevelMaths2025]

Nicely explained sir as usual!! Great intro and outro music!!

[@TheGCSEMathsTutor]

Thank you 😁🙏🏼

[@leia2017]

11:45 would i get the mark for the second question if it was simplified

[@goat2692]

🤫

[@thelmaashibuogwu8162]

Yeah

[@lolllhello7718]

Helped me a lot

[@TheGCSEMathsTutor]

Lolll Hello Great to hear 😁

[@everythingtv4875]

will u still get a mark if u simplify it?

[@GamingWithJas-ff4yf]

As a set 1 i see people in the comments who find this harder than i do, and im the one thinking im bad at maths when it is easier for me to understand this at school then everyone else.

[@m7md_jawad]

One doubt in the last question JACOB takes 2 sandwiches at random isn't we supposed to minus 2sandwiches from rest all in the second branches like 20/9 instead of 20/10

[@minecraftlovaaa]

that’s exactly what i’m thinking i’m confused by that as well

[@elecaniv_0077]

@@minecraftlovaaa lads its just worded weirdly, it basically means he took one-then im guessing ate it, then he took another. so in essence he takes one, then he doesnt put it back AND THEN HE TAKES ANOTHER.. which is why it is minus one

[@elecaniv_0077]

another way to say it is...The question is worded strangely, when it says “two sandwiches are removed” it means that one is removed, checked and then a further sandwich is taken on the second pick. So hence on this tree only one sandwich is removed by the time we reach the second branch. This language always confuses students in exams!! 😁🙏🏼

[@ibraheemali7044]

great revision video thanks

[@TheGCSEMathsTutor]

ibraheem Ali Thank you 😁🙏🏼

[@estheraiyelabola6933]

Hello Mr. GCSE Maths Tutor, thank you for replying to my message. I have another question, for the second question, why wouldn't the 2nd bag be over 5? Thank you for always responding!

[@estheraiyelabola6933]

Please don't worry, I understand now!😁😁😁

[@senanamin9474]

@@estheraiyelabola6933 im confused why would it not be out if 5

[@Sharon_.x]

thank you so much god bless you 🙏

[@oliviaaa2324]

could you please make a video on conditional probability?

[@TheGCSEMathsTutor]

This is conditional probability 😁🙏🏼

[@oliviaaa2324]

@@TheGCSEMathsTutor by that I mean questions that have the 'Given that...'. do you understand what I mean?

[@TheGCSEMathsTutor]

@@oliviaaa2324 hmmm do you have any example questions? I’m sure I’ve covered it all! 🙏🏼

[@oliviaaa2324]

@@TheGCSEMathsTutor in conditional probability questions you usually get wording such as "the probability that event A happens given that event B happens." that kind of wording confuses me personally and some questions are usually without tree diagrams. An example of a question:

[@oliviaaa2324]

90 pupils were asked whether they owned a laptop or a tablet device. 52 said they owned a laptop. 45 said they owned a tablet. 23 said they owned both. Find the probability that a pupil chosen at random owns a laptop, given that they own exactly one device.

[@jarzo9259]

thank you so much

[@frizzyred1292]

But what if it's two reds he takes out? This is what confuses me. We are assuming he takes one red and then one blue. Help!

[@TheGCSEMathsTutor]

You can only work on the assumption that one is taken at a time! 😁🙏🏼

[@hemanthsai6161]

@@TheGCSEMathsTutor oh i get it thanks

[@samuellacobbinah]

Please why was the second set of probability 2/6 and 3/6 instead of 1/5 and 2/5 ? because in the question, Cameron takes at random, two counters not one counter from the bag.

[@SaqibRiaz-nr3zv]

Don’t move your legs move your mind sis!!!!!!!

[@themeredithbros3488]

Sir, i do not understand, when it says you take two biscuits out, shouldn't the denominator decrease by two and not one?

[@justsomeone5660]

yup same, have u figured it out yet?

[@symcow8743]

@@justsomeone5660 just assume that 1 counter is taken

[@richardcollom1655]

Are the answers still correct if simplified...

[@djamilaaaxo]

17:57 / 20:19

[@ia58]

Thanks a lot

[@Estella473]

5:56 will I still get the mark if I simplify it my answer in calculator is simplified (15/28)

[@Estella473]

Or if I write it as decimals

[@jituwu]

u dont need to just leave it as it is@@Estella473

[@magpiestudent9357]

Caroline learned the hard way that all of 20 of her biscuits now taste of ginger.

[@tmax959]

Thank you

[@roseanne9020]

thank you 💘

[@Khaldoon.Arshad10]

Thank u so much. Sooo helpful🙂🙂

[@TheGCSEMathsTutor]

You're welcome 😊

[@lolllhello7718]

1st like aswell

[@TheGCSEMathsTutor]

Lolll Hello Haha love that 🙏🏼

[@rayhaan7860]

go have a medal

[@lamiyakhokon890]

the second question could be an independent event, right? or is it just dependent? if so then why.

[@TheGCSEMathsTutor]

It is a dependent event as the probability of the second counter is dependent on the colour of the counter taken out on the first pick 😁🙏🏼

[@lamiyakhokon890]

@@TheGCSEMathsTutor thanks. got it. great video btw. :)

[@craigthornton8154]

Thankyou sir

[@samuellacobbinah]

Please the question that says, work out the probability that Ollie takes two of the same coloured counters, why didn't you multiply the probability of getting only red counters and only blue counters by two before adding them up. Because the question said the probability of two same coloured counters.

[@Gh_Manchester]

My thoughts too.

[@GamingWithJas-ff4yf]

OR = Add AND = Multiply

[@chachachaudhary391]

thanks a lot 😁💥

[@darnellbailey5038]

🐐

[@harisamaan786]

Last question. Was in my exam I'll tell you what I got out of 54

[@TheGCSEMathsTutor]

Best of luck! Hope it went ok!

[@harisamaan786]

@@TheGCSEMathsTutor 52 out of 54 the last question was a tree diagrams but it wasn't that simple it was triple tree event can u do a video on it

[@affanhadi3123]

Thank yu

[@TheGCSEMathsTutor]

You’re welcome 😊

[@amronyt7]

ty

[@rayhaan7860]

im so dumb i watched the grade 7-9 playlist and got a grade 4 cuz i didnt know some of the first half of the paper

[@rayhaan7860]

what should i do pls tell me

[@h_arks9691]

@@rayhaan7860 go over maths genie revision work sheets (they're by grade). You could also do some past papers for the foundation.

[@rayhaan7860]

@@h_arks9691 nah not foundation im doing higher for gcse

[@Nilashaaaaa]

I still don’t get it

[@tyrionpapersdotcom]

tsym YOU are amazing when the teachers were explaining it at school i did not understand and when i watch your videos i understand

[@kpopstan200]

i dont understand

[@juhaalo7753]

It’s funny how the video is 20:19 minutes long

[@samreenimtiaz3075]

Its not ending on 2019 it is ending on 20:20

[@Maxtreon.]

Smh these guys be offending they teachers untill they get back to school only to realise they teachers been knowing it all along. Yall just play the fool in school and be a big brainer at home. Yall selves to blame.

[@GamingWithJas-ff4yf]

As a set 1 i see people in the comments who find this harder than i do, and im the one thinking im bad at maths when it is easier for me to understand this at school then everyone else.😊

[@GamingWithJas-ff4yf]

As a set 1 i see people in the comments who find this harder than i do, and im the one thinking im bad at maths when it is easier for me to understand this at school then everyone else.😊

[@zaharakhan1370]

who asked

[@GamingWithJas-ff4yf]

@@zaharakhan1370 you just did