Probability Equations | Grade 9 Maths Series | GCSE Maths Tutor

[@TheGCSEMathsTutor]

Small correction! The first question should state ‘The ratio of green to blue is 4:1’ in the second line 😁 not sure how I missed this, I tend to go into auto-pilot! 😁🙏🏼

[@ゆじ-d5i]

17:50, should it not be x-2 due to it says 2 are taken out?

[@user-tg1zf6ow4o]

Thanks I was looking at the questions and trying to do before you started and was really stuck because it didn’t make sense but saw you message thanks a lot for all videos though they really help!

[@zakariya_fn3412]

@@ゆじ-d5i im a year late but yh its supposed to be x-2 I'm sure I don't think he read it right

[@makesandbakes9356]

@@zakariya_fn3412it’s not because he take one out originally then takes another which makes two so it’s the same as all the other questions but just different wording I think

[@studyonly780]

@@ゆじ-d5i no because he does take out two but separately, so he takes one out first and then takes another out from the second fraction

[@thegreatgojousatoru5846]

amazing video. good for half term easter revision. good luck to all the yr11s doing gcses this year 🙃

[@jamsi1066]

thanks !! im revising so late lolol i have rs tomorrow

[@thegreatgojousatoru5846]

@@jamsi1066 same i have re tommorow lol

[@jamsi1066]

@@thegreatgojousatoru5846 good luck !!

[@thegreatgojousatoru5846]

@@jamsi1066 you too!

[@mxxced]

Its tomorrow and ima win I have decided

[@enlightenedsoul8897]

Man, this helped, not just with probability but also helped with my algebraic fractions and quadratic equations. So thanks for this

[@TheGCSEMathsTutor]

So glad to hear that! It’s an awesome topic.. so many skills tested!! 😁🙏🏼

[@hassan-sg1eq]

this videos was made three yrs ago and is helping me rn Thankuu

[@PelumiAyo.]

Thank you so much for this video Sir, I literally remember doing similar questions to these in a lesson and I was so confused. But after watching your video I feel more confident with this topic. Thank you so much, sir.

[@TheGCSEMathsTutor]

PELUMI That’s so great to hear! I’m so glad they are working for you!! Keep up the fantastic work!! 😁🙏🏼

[@ゆじ-d5i]

For 17:50 why did you not do x-2, it says 2 counters are removed not one and you don't necessarily know as a student whether this is a red counter or whatnot.

[@sxshxprx]

thats what I'm thinking

[@muskanazimi9110]

i know this is late... but its not x-2 because that only the amount of counters left in the bad AFTER both rounds, he has only taken one out so far so the amount of counters in the bag is x-1.

[@ka-ox5wf]

youre honestly the best maths teacher out there

[@TheGCSEMathsTutor]

Thank you so much for the kind words, I really appreciate that! 😁🙏🏼

[@maryamahmed5244]

For the question at 14:03 It says take 2 counters so won’t it be 5/x+5 x 4/x+4 x 3/x+3 Because isn’t the 5/x+5 the original one

[@_cycl0nes642]

that's what i thought

[@ims_coolcat_2334]

That's why I was confused but I think I've understood that basically when it says "2 counters are taken", it's just referring how if the person took a blue firstly, then the chances would be the original fraction as nothing else has happened. If they were to take another blue, the chances would be 4/x+4 as the previous counter taken wasn't replaced. If it was multiplied by 3/x+3, that would be "3 counters taken" instead of 2. so as it's two goes, you would use the original multiplied by the next probability (4/x+4). Hopefully that makes some sort of sense. It made more sense thinking in my head than typing it ahaha

[@aysh3463]

@@ims_coolcat_2334 u said it exactly how I would say it. I remember doing a question like this in class and there was some confusion of the 2 counters removed but then it came clear when our teacher pointed out that It counts as one followed by another

[@ibraheemahmed828]

@@aysh3463 so if it was two RANDOM counters then would it be 3/x+3?

[@hh-ms3ub]

thank you so much i need this for my yr 10 mockss

[@nuzhahussain4981]

At 17:37 why do we do x+3 because in the question is says 2 counters are removed not 1?

[@TheGCSEMathsTutor]

When it says 2 are removed this is working on the premise that 1 is removed, followed by a 2nd counter! Not language that I am particularly fond of but you will never remove more than 1 at a time in these scenarios even if it said that 10 were removed.. we would just have a ridiculously long tree diagram! 😂🙏🏼🙏🏼

[@KazACWizard]

thank god youre here, i am acc going to get a 9 bc of YOU tysm

[@sadiaafzal4479]

Shuuuuuuuuuuuuuuuuush

[@user-my7te8ot8l]

You so will

[@mohammednaqi5166]

تعال شمه

[@zainebh4969]

What u got

[@KazACWizard]

@@zainebh4969 Im in Uni dude ;) wbu?

[@sadaftamkeen7423]

Thanks this was really helpful! but I was wondering if instead of at 6:00 when you turned the equation into a quadratic, wouldn't it make more sense to instead add 140 to -110 and that way you would've gotten 10x^2 = 30x and then you could've solved it to get x = 3 (but does that work everytime or was this a one off?)

[@EliteEGG101]

the double and half method... i needed this

[@JpKizzy]

You can take out x as a common factor on the numerator and denominator to avoid solving a quadratic 👍

[@dylanking8032]

For the first question i find it easier to cancel the the x's when it was 4x/5x which makes it easier to solve as you don't have to factorise.

[@midnighteddy1672]

last minute revision for tomorrow! this is great thank you!!

[@anonymous-kz5gs]

how did it go?

[@7nthrock508]

omg than you so much i have the igcse 2H tmrw and i was worried about probability but you got me covered thank you so much

[@Youtubeeeeee123]

Maths paper 1 tomorrow good luck guys

[@saangapasoon]

How did it go

[@Blah5641]

​@@saangapasoon great

[@mano8783]

thank you!!!!!

[@TheGCSEMathsTutor]

bybangtansside My pleasure!! 😁🙏🏼

[@connorranson4769]

honestly you teach it so well, do you have any videos on how enlargement affects area and volume as i cant find anything, thankyou

[@TheGCSEMathsTutor]

So glad to hear that! Absolutely here it is: kzbin.info/www/bejne/nJ27lauLmJyqgck hope that helps, thank you for the kind words 😁🙏🏽

[@Hi-uj4zj]

@@TheGCSEMathsTutor Hi thanks so much for the video!! I was just wondering is this probability what is meant on the aqa advances notice higher?

[@yaseenhussain]

Hi, for 17:36, why did you do x-1 and not x-2?

[@laylaanis540]

that's what I was wondering

[@BossBoss-wx6mx]

is question 1 a trick question because it says ratio of green to BLUE counters but then it goes on to say the ratio between green and RED is 4:1

[@TheGCSEMathsTutor]

It’s actually a mistake in the question it should say green to blue is 4:1 not green to red 🤦🏻‍♂️🤦🏻‍♂️🤦🏻‍♂️

[@BossBoss-wx6mx]

The GCSE Maths Tutor haha it's ok I got it 😂

[@TheGCSEMathsTutor]

Boss Boss Great to hear!! 😁🤦🏼‍♂️🙏🏼

[@huilinnnw4907]

Hi, just wondering why don't you cancel the x (e.g. question 2: instead of x/4x, you can do 1/4) , this way you don't get a quadratic equation and you can work out x to be 4 straight away?

[@seadrown6252]

skibidi bop mm dada

[@memetris6971]

17:35 why did you remove 1

[@TheGCSEMathsTutor]

We can only work on removing one after the other, even if we take 2,3,4 counters etc 😁🙏🏼

[@nathanhawey294]

waw I fully understand this thank you the best teacher ever.

[@tb9430]

22:35 Why do we have to make it equal to -1 ?

[@shmackedog2551]

your factorising n^2-n-90 also known as 1n^2-1n-90 and if your familiar with basic factorising your therfore trying to make the 9 and -10 equal -1 hope that makes sense

[@mrgoatliri6224]

22:30 I got same answer but did n= x+6 when doing probability diagram and got correct answer but would I get full marks for working??

[@TheGCSEMathsTutor]

I cant’t see why not if your algebraic method is sound! There are usually different ways of approaching these kind of questions 😁

[@ufaclips]

@theGCSEMathsTutor is this still the same today cuz i did mine the same way as @mrgoatirli6224

[@MKhan-qe9lp]

8:26 and 17:00 to the end exam practice.

[@muscledsteak]

This intro is to fire to be a math video. 😭 Good video though. 👍

[@ebude9376]

hello sir, for the last question you did I tried doing it before you but instead of 6/n x 5/n-1 I did 6/n+6 x 5/n+5 and continued working out the answer. I ended up with 10 sweets too

[@roshankukadia9041]

Is this condition probability?

[@enlightenedsoul8897]

Legend has it, there is one probability question that has all the maths in the world

[@TheGCSEMathsTutor]

Haha love that! 😁🙏🏼

[@jesy._.vxln7512]

in the third question it says two counters are removed so are not we meant to take away 2 ? i am confused

[@blinkeditor__]

No you only take away 1 it’s just the way the question is written that makes some students think that they have take away 2

[@jameskelliher]

Great vid needed to go over this as I always go slight off on these questions

[@cyclonegamer3417]

Thanks for the video.Do You know where I can get more questions on this topic.

[@kawlanonya833]

did you end up finding a place? I literally tried everywhere and I couldnt find anything as hard like this 1

[@Yani_122]

@@kawlanonya833 maths genie and Dr frost maths

[@crazymemes2832]

how i felt after solving last question alone 🗣🗣🚬

[@checkpoint2189]

fr

[@idontknow1630]

thank the lord I've found this... ever since we did it in class I was completely bamboozled until now. I'm pissed off at myself at how easy that is! How is that a grade 9 topic?

[@TheGCSEMathsTutor]

Always a good sign that you’ve gone from bamboozled (great word btw!) to finding it easy over the course of the video! I’m assuming it’s helped then? 😁 any other topics that bamboozled you?

[@idontknow1630]

@@TheGCSEMathsTutor The video helped a lot, thanks a bunch man. I'm doing fucntions rn and I'm a bit 50/50 on that. The worst topics for me are loci and congruence.

[@rayhaan7860]

@@idontknow1630 same for me loci i hate it

[@milliegrace7394]

I'm confused as it says 2 counters are removed but I dint know where that comes into relevance. help please ! :D

[@crazymemes2832]

oh

[@harisamaan786]

This topic is very hard but thanks alot i didnt understand it at all noe i understand out of 10 8 out of 10 thanks very much

[@44bor]

Can you please do a harder version of this?

[@TheGCSEMathsTutor]

Have you seen any harder questions anywhere? 😁🙏🏼

[@MKhan-qe9lp]

A levels is an afterthought😂😂

[@HRS-gi6xp]

@@MKhan-qe9lp this is gcse u shmuck

[@worldofortnite5731]

1:31 where did the red go

[@TheGCSEMathsTutor]

Please see pinned comment 😁🙏🏼

[@worldofortnite5731]

@@TheGCSEMathsTutor, my bad .....;)

[@erenyeager6668]

for 3:12 shouldn't it be x-1/5x-1 for green---> blue, why did you do x/5x-1

[@naimax8205]

you know at 17:38 you said take 1 red counter, but the question said 2?

[@Masowe.]

tank you so much for this video, now i am confident enough in probability with algebra!

[@TheGCSEMathsTutor]

COSTIE TV amazing!!!! This is a difficult topic so that’s so great to hear 😁🙏🏼

[@Masowe.]

@@TheGCSEMathsTutor i am happy happy to hear that too. With your videos i am hoping for a 9. Now i am going through playlists while waiting for new videos!

[@TheGCSEMathsTutor]

COSTIE TV Amazing!!! New ones will be coming but we all need a bit of a summer holiday! You are clearly super proactive so good on you, keep it up! 😁🙏🏼

[@Masowe.]

@@TheGCSEMathsTutor i agree with you 100% there . It is nice and health to have holidays. Have fun with all your loved ones; i will be practising a lot during this time! Thank you so much for good wishes and your time!

[@TheGCSEMathsTutor]

COSTIE TV Absolutely! Enjoy the rest of your holidays 😁🙏🏼🙏🏼🙏🏼

[@rightrey7641]

Thanks for the video, really get the topic now!!

[@TheGCSEMathsTutor]

Rightrui egdbufj Great to hear! 😁

[@joseph_donovan]

I wish my edentate granny had known about probability equations when I asked her if should ask Griselda out to pick blackberries with me. My granny, who was partial to snuff, said Griselda could only say Yes or No to my invite, so I should ask her out. Griselda laughed manically and shrieked: "Ha! Go out with you? I would sooner tickle a pink-footed tarantula's belly with my tongue!" Perhaps the snuff clouded my granny's probability prowess. After this masterful video, I now see where I went wrong. Thank you!

[@bobsham9136]

3.18. Sorry I don’t get why you did 4x-1 over 5x-1, and then you did x over 5x-1 for blue. Shouldn’t it be x-1 over 5x-1?

[@TheGCSEMathsTutor]

Bob Sham On the part of the tree you are talking about only 1 green counter has been removed. Writing x-1 as the numerator got blue would indicate a blue counter has been taken which it hasn’t when looking at the route where only a green has been removed 😁

[@bobsham9136]

The GCSE Maths Tutor I get it now. I was taking away the wrong colour. And sorry to disturb you again at 17.44 in the question it says 2 counters are removed from the bag. But when you do the branch you put x-1 over x+3. Your probs right but don’t get why you minused one not 2, as it said two counters are removed. Your probs right, it’s just that I don’t get it. You can tell this is not my strongest topic ahahahah. But thanks again!!!

[@TheGCSEMathsTutor]

It’s a difficult topic! When it says 2 are removed, the first cluster of branches represent the removal of the first counter, hence the -1, the second set of branches represents the probability when the second counter is removed 😁 you will never subtract 2, the mathematics behind that is a lot more complicated!

[@bobsham9136]

The GCSE Maths Tutor okau. I think I’ve grassed the concept. I’m just going to try do as many practise questions as possible. Thanks.

[@TheGCSEMathsTutor]

Bob Sham Great to hear! 😁

[@Mehdi-cw4cx]

for the first question, should i cancel the two x's

[@sahilaziz5718]

Thanks this was really helpful.There was a question on the 2019 paper 1 at the very end that was extremely hard.Could you please make a video on it thoroughly explaining it.

[@TheGCSEMathsTutor]

TEAM Bantz!!! Great to hear!! 😁 I cover the question you are talking about in this video: The 10 Hardest GCSE Maths Questions & How to Solve Them | Grade 9 Maths Series | GCSE Maths Tutor kzbin.info/www/bejne/b4nEY2ykjMSKj6M

[@sahilaziz5718]

The GCSE Maths Tutor thanks so much!

[@muskanazimi9110]

so is x squared even?

[@GCSEALevelMaths2025]

Really good video sir good job!!

[@S123-x5b]

Thanks for the video ❤️❤️❤️

[@TheGCSEMathsTutor]

Sonia Galiza My pleasure! 😁

[@S123-x5b]

The GCSE Maths Tutor how old are you?

[@bellastarmartin4601]

Excuse me sir! On your channel you used to have videos going through past maths exam papers,how come you took them down?

[@thehemidemisemihemidemisem3339]

I am revising hard on probability even though this test is not that important

[@ooneyooser2967]

in the second question it says 2 counters are removed so how come its only one thats being removed??

[@shanicetylersvlogs8554]

thank you so much, love this channel

[@darciamelia4753]

Thanks this was amazing

[@TheGCSEMathsTutor]

So glad to hear I could help 😁🙏🏼

[@Rafmee]

Hi sir is this topic normally in the calc or non calc papers?

[@divsm6503]

Non calc

[@kathrynlea-wilson6883]

THANK YOU SO MUCH❤️

[@your.favorite.detective25]

Hey, first of all thank you for all your videos they've seriously been a big help. I just wanted to ask, is there a playlist for probability? Cause I've been having to go back and forth from a video to another and I don't want to miss any.

[@altritzy8550]

yes he has it on his channel

[@sk0266]

really helpful man thanks

[@dskiis]

For the very last question, I had n=4 and n=-15, however still got 10 sweets. If i were to answer like this in a real exam would I still get full marks?

[@kawlanonya833]

TYSMM. I understand this topic. but im trying to find other question that are hard like this but I can't find any. could you recommend me a website to use or a place that has hard Qs like this

[@farhia3132]

thank you this really helped

[@sahnafthehumble7252]

One question, the problem at 17 minutes, the info of there being 2 counters removed: Is that irrelevant??

[@shayaanhussainshah6273]

Yes I think he made a mistake I can’t lie

[@michaelakata4404]

It is because you can only pull one counter at a time and if you were to take 2 counter the probability tree would be very long.

[@Jack-vc2tf]

Thank you so much

[@khaledaa4u322]

The Internet is better at math than my teacher

[@TheGCSEMathsTutor]

Glad the channel is working for you 😁🙏🏼

[@khaledaa4u322]

@@TheGCSEMathsTutor thank you I managed to finish my homework because of you guys

[@TheGCSEMathsTutor]

Amazing news! Keep it up 😁🙏🏼

[@khaledaa4u322]

@@TheGCSEMathsTutor thanks

[@asmaa1853]

thank you a lot

[@ゆじ-d5i]

Life saver

[@TheGCSEMathsTutor]

So glad to hear it 🙏🏼🙏🏼

[@swldnsstory9843]

Both Statistics papers being calculator papers is my excuse for using a calculator rnn 😂😭

[@rubyh2064]

so confusing still dont understand all the end bit

[@TheGCSEMathsTutor]

The end part of each question consists of solving quadratics so this video might be helpful: kzbin.info/www/bejne/oZ7IfWeXaNF6a9k if it’s another part of the questions let me know and I’ll see if I can link some other videos! This topic is not an easy task 🙏🏼

[@ChandiPerera-yt4oq]

removed 2 but it is removed 1 am i wrong

[@JessicaChloe]

I genuinely feel like I have been moved up a set by mistake...

[@halah822]

self doubt is so bad for your mentality , work out why you feel that way , and CHANGE IT , you deserve to be moved up a set and work to stay there or move up a higher set if there is one ,

[@thatonekidonaboat1269]

I dont get how 4x multiplied by 4x is 16x^2, surely it would just be 16x

[@riaasx]

there are two x's therefore multiplying them together is x * x which is the same as x^2

[@pranaydave5536]

Bro think of it as (x × 4)(x × 4) and that will give u 16x²

[@enlightenedsoul8897]

20:38 The Meme Question

[@adili2405]

Ty

[@darrenebosele]

who else alr knew dis topic n got every question right 🙋🏾‍♂️

[@zcharredhydrax5105]

do i will use these probability trees i my life?what a waste of time....

[@TheGCSEMathsTutor]

Not all maths topics are functional skills based, there is a mixture of functional skills along with pure mathematics, pure mathematics topics such as these are for the progression of mathematics into A-Level and degree level mathematics! So I appreciate that some may find this a waste of time but it’s entirely dependent on which field you want to specialise in moving forward 😁🙏🏼

[@SockerTom]

nah but exams exist bro

[@Ur_neymar_jr]

yawnn