Probability - Everything You Need to Know. 11 New Tricks and Shortcuts, GRE, GMAT and more

That’s right, everything you need to know for probability. And versus Or, with replacement and without, specific orders, simplifying probabilities, ratios and probability, probability formula, ‘at least’ in probability, probability and combinations, using venn diagrams for probability, independent probabilities, repeating probabilities until event occurs, letter arrangement probability. If you don’t learn something, I’ll eat my hat.
And it’s not just for GRE and GMAT students wanting probability questions and difficult probability examples, it’s for any student wanting an introduction to probability.
I offer private GRE / GMAT tutoring online at a fixed rate of $140/hr. Please get in touch via the email below, or through my tutoring website: www.gretutorlondon.com/
Enquiries: [e-mail]
The GRE and GMAT are two of most used graduate exams for those seeking to study a Masters Degree or Masters in Business Administration (MBA) degree. The Graduate Record Exam and Graduate Management Admissions Test have been taken for over 50 years and are taken by approximately 600,000 and 300,000 people worldwide annually, respectively. These exams are typically taken between the ages of 18-40, by those who have completed, or are about to complete, their Bachelors Degree.
Business Enquiries: [e-mail]
Grateful for any support: / testedtutor If you’re now ready to get into your dream MBA program, my former student, Angel, is offering virtual private Admissions coaching. She was admitted into Harvard Business School, The Wharton School of Business, and Columbia Business School (accepted into every school she interviewed for) after graduating from UCLA with a degree in Communication. She also got 3 perfect scores on the GRE’s Analytical Writing Assessment (99th percentile).
Here is her link - linktr.ee/angel_accel - and you can reach her at [e-mail] with the subject line, “PHILIP SENT ME.”

[@RyuStardust]

HI Philip! I gave my GRE today after binging your videos the past week. I had gotten a 313 (160Q, 153V) in my first attempt and got a score of 326 (170Q, 156V) today! I can't thank you enough for theses amazing videos. Those little quant tricks on mixtures, weighted averages, ratios, and probabilities helped me save so much time in my quant section today which certainly boosted my score by a lot. Thanks again for putting up so much free content for everyone to see, this definitely did the trick for me.

[@TheTestedTutor]

Wow, a perfect Quant score! Great job Sparsh and thank you for the kind words.

[@tejal8382]

How many mocks you gave ?

[@bashu70]

Hi ..sparsh..I am planning to give GRE in Nov..pls guide me how to start from

[@ashleeT]

@SparshJain how did you prepare for quants and verbal?

[@karishaananyaneelakandan413]

How to score 150 plus in verbal

[@TheTestedTutor]

At minute 38:15 the answer choices should read 0.10, 0.12, 0.18, 0.28 and 0.30. Well spotted ctlr9k!

[@NC-vk6xe]

Hi Philip, I just wanted to say thank you!! Your videos are amazing and perfect to catch up on a lot of topics all at once. I got a 325. I couldn't repay you in any way, so I helped someone else who was taking the test and prayed for you. Just wanted to let you know that I'm so grateful for your work! Thanks again.

[@rajasekhar6058]

Hey philip! I gave my GRE Today after going through your videos. I secured 312 (161 q, 151 verbal). My score increased from 290 to 312. Thank you for your service for community.

[@TheTestedTutor]

Well done Raja!

[@himanshnama7365]

hey raj, hw long it took u to increase 22pts

[@Motorcyclegymnast]

Hi Philip I just wanted to say you are the definition of work smarter not harder…I spent countless hours trying to memorize all this crap and learned way more in your videos. Your teaching style makes it easy to follow along! Thank you so much

[@stevensosa5995]

This just makes so much sense when you explain it. Thank you so much for your help! I struggled with the probability questions on my practice exams and in the actual GRE, but you make to so simple.

[@ghadahahmed3471]

Hello philip, I am coming to express my gratitude 🙏🏻 for all your videos especially the 5 weeks quant section, throughout the past 3 weeks I have been watching most of your videos, and I re-entered the gre general exam and my grade have raised for 10 points . Thank you so much for your great efforts (from Egypt 🇪🇬)

[@prabhudattamishra7245]

Hey Philip! I was kind of waiting for this day when I could write a message to thank you. I gave my gre today and scored 321. I can't thank you enough!! You are the best teacher one could ask for😋😋

[@avinashks3258]

Hello Philip, what was the final option for the independent event question? 0.3--0.12 = 0.18 doesn't equate to any of the fraction in the answer choice.

[@applepeel1662]

exactlyyy

[@lizwilliams97]

I was thinking the same thing! Couldn’t find the answer online.

[@hogrideeeeer]

⁠@@lizwilliams97the answer is 0.18

[@oneepicsaxguy6067]

A very nice video! Knowing combinatorics really helps with probability, but your video showed an alternative way for all these problems which now makes it easy for me to cross check!

[@osaidqasim5103]

Thank you so much for this amazing and smooth teaching, I’m so lucky that I’ve found this video.

[@tarunraghu1]

Happy Teacher's Day Philip !!!! . Your videos have helped me immensely in my preparation. Hoping to get a good score. You are venerated by all of us. God Bless

[@mimkhandaker5082]

Thankyou for making these videos. I’m taking my GRE in about 2 weeks and I’m binge watching all your videos. Great help!

[@dominicmutiso1502]

how did it go?

[@ayushsrivastava9997]

Man this video is probably the best of your videos I scored 161 from the previous 151 Thanks a lot mate 😊

[@aceallen2505]

I recently took GRE and scored 314 (156V, 158Q, 4.5 AWA) in my first attempt. Though this is not as high score as 340, I am content as it would land me in a coveted University. I would thank Test Tutor for all the insights. Hope you make more such videos with these little but highly lucrative tricks. You are a constant impetus, and it is always quelling to watch you videos- keep up the good work 🙌

[@TheTestedTutor]

Thanks so much Ace

[@swoooshfloop]

So helpful - thank you so much. Been binging your videos!

[@ktheman1]

hey mann youre a real g fam i have my GRE tmr imma ace it cuz of your help (hopefully!)

[@oneepicsaxguy6067]

Hey, I gave my GRE exam today and scored 327 (V 159,Q 168). Although I have a maths background, your math videos really helped me brush up my topics and learn a few tricks too (weighted average trick is golden). Thanks for the help!

[@TheTestedTutor]

Well dobe my man!

[@DeepakKumar-rz9wq]

I have no words to thank you enough for this video..!!! 👍

[@takuminishi6789]

Hey Philip! Thanks always for the great content regarding GRE, personally I've never been more confident in quants after watching your in-depth videos. Just a question, do you have a dedicated quantitative content specifically to square roots (and/or cube roots)? If you haven't yet, I would be grateful if you can create about it soon! (cheers!!!)

[@uchihaichizoku]

Very nice video Philip! Thanks a lot!

[@tejal8382]

You are the best ! The way you explain even the most complex concept in a such a simple way no one else can 😊

[@tejal8382]

Hey, Philip I want to get tutions from you is it possible plz do reply 🤞

[@tejal8382]

Can you plz help me with tutions

[@yashghatlia]

Hey Philip! I just gave my GRE today after binging through your over the past couple of weeks. Was initially struggling with time management throughout my mocks, but managed to get a 326 (163/163) today! Wanted to thank you for all the tips and tricks. Your channel is gold and I’m going to recommend it to everyone I know who’s preparing for the GRE! Cheers :)

[@TheTestedTutor]

Incredible. Well done Yash!

[@umairahmed1773]

One of the hardest topics on GRE Quant. Really happy you considered it for a video. I wish you could arrange all your videos in a complete step by step course of quant and verbal. Please give it a consideration. Thanks!

[@TheTestedTutor]

I have! Check out my 5 week playlist

[@umairahmed1773]

@@TheTestedTutor oh, I will check it. Thx Philips

[@gre341withsaadamer]

Just saw this video of yours. Excellent content. Keep up the good work!

[@TheTestedTutor]

Thanks Saad

[@techbasics4481]

I'm from India and have recently started watching your videos. Completed almost all the playlists and indeed this is the video I've been waiting for. Thank you for all the teaching & content that is utilised by millions of students around the world. I have my GRE, a month from now approx. and wish me luck. Thanks mate :)

[@TheTestedTutor]

So glad! Good luck TB!

[@pavansiddharth2279]

atb

[@ally12345]

How was your Gre?

[@payalpal4386]

Hi Philip, can you kindly include a detailed lesson on standard deviation and statistics, including a set of challenging questions.

[@cholocatelabs]

A great collection of questions:

[@LEYLAKHANAHMADAZE]

Thank you, this was very helpful!

[@esraamansour3405]

oh my god, this video is too hard for me, I need to practice more on probability problems, very valuable tips.

[@ahmedalajlouni7173]

Out of a blue. Honestly you are amazing. Incredible! How did you know exactly where I fail? Are you such a wizard?😅 Actually I got insane when you mentioned where most of students got wrong. You're amazing bro. I am totally thankful for you, whatever I say is less then you

[@b3ast407]

Thankyou very much!!, i am taking gre in 12 days, i needed exactly this.

[@TheTestedTutor]

Glad it helped and good luck Beast!

[@b3ast407]

@@TheTestedTutor Thanks!!

[@sanskrutisharma4197]

So helpful!

[@mumtahinahzia7312]

Awesome Mr. Philip..I have done magoosh twice but your videos are better and easy to understand...

[@mumtahinahzia7312]

But I have one question..In the sibling question, why we didn't consider another scenario that if I take one child from second class (25 student class), and then first class, the total calculation would be (3/12*1/25) 0 +3/25*1/12) . Please let me know...

[@valentinatoby3762]

Thank you phillip

[@hagoskalu7293]

Your videos are amazing. Keep it up.

[@MindOverMatrix111]

Done with my GRE but um still watching Philip cause I love his content. ❤️

[@TheTestedTutor]

very cool

[@ashishsinha9035]

Very good Philip!

[@ChessQuickies]

Hi Philip! These are absolutely great videos, and have taught me so much! One request - could you make cloze videos? The type of cloze where you have to fill in the missing letters of words in a text? I know it usually doesn't come up in the GRE or GMAT, but it came up in my 11+ exam. Are there any techniques for being faster, or have a more efficient mindset for coming up with possible words? Thanks! Ps. (Not trying to be rude) If you don't have much information on cloze or can't find out what sort of questions it has - since it doesn't appear in GRE or GMAT - could you make distance videos? thanks once again

[@sreejasree7427]

Thanks sir 😊

[@reddaxtor5662]

Thanks teach!!

[@VallabhEv]

thank you so much for this video! the different kinds of problems were really helpful. love from india :)

[@TheTestedTutor]

Glad it helped!

[@ishworshrestha8361]

WORTH WATCHING

[@MariaRomero-bw7uy]

Hi Philip, thank you so much for your videos. I followed everything, but I have a question. In the twin example at the end of the video (around min 46) don't we have to add the probabilities of the other two sets of twins? Making it 3%

[@vishrutmahi6593]

This is the best guy for GRE out there

[@TheTestedTutor]

Thank you. I agree

[@msk27vlogs]

Great Work Philip!!! Appreciate your work to give us such a useful tricks.

[@patsy7514]

41:11 Why should it be one choice followed by another choice and not picking both gloves simultaneously? Which part of the question helps us come to this conclusion?

[@mostafadastgheib63]

Dear Philip, For the unexpected probability trick (48:01), shouldn't we take the orders into consideration, and do the calculations for another time when we first pick the sibling from the class of 25 and then 12? meaning: 3/25 multiplied by 1/12? and then sum it with your answer.

[@TheTestedTutor]

Because with the twins you NEED to pick a twin the first time (no twin = fail), and then you NEED to pick that twin's one sibling (which is why you don't multiply by all the twins in the second class). But with the bag you can EITHER pick up red first, then green OR green then red. It is a more flexible situation with more routes to success. It's the same reason we don't count H H (two heads) as different from H H (the same in reverse order). If we need two heads (like a twin pair) then first option must be a head (H), no alternative, no repeat or reversal

[@user-ph4sz9xc5e]

Hey Philip, For the question on 24:50, if I happen to choose the longer method of listing all the scenarios using letters and finding the probabilty, is there a way to determine that there are 15 such events. like how can I know that 15 events of snow and no snow is possible?

[@JasmineKhamis-un6pb]

Hello Philip! I really can’t thank you enough for your videos; you’re helping accelerate my studying by light years! I just have a comment on this particular video about the ‘independent’ question; we computed the answer of 0.18 but it is none of the multiple choices given. Did we miss a step? Or was it the wrong set of answer choices?

[@sathyanaarayan3694]

Hi Philip same doubt here!

[@thedialogues9435]

A beginner Friendly video and also starts with question and explains the application along with it . Helpful to build concept at a grass root level which is very much important for Medium to hard level questions. so if somebody wants to start probability look this video first and then go else where

[@nailahasan7827]

@The Tested Tutor, in case of disguised venn diagram, I have something to say. Actually the the probability of both event occurring is (0.4 * 0.5)=0.2=20%, Otherwise it doesn’t get matched with probability logic of two independent events. If they weren’t independent, then the word “both” wouldn’t come here. Please tell me if I’m wrong here.

[@nanabaffour8820]

Please how will you know whether you need to work out what you're not asked for and subtract from 1 or to work it out straight away?

[@dilbarmm10]

Hello Philip, In 19:23 what's the importance of "the next two interviews"? If it is the next 3 interviews would the answer be the same?

[@palakjangra8808]

Hi philip I am planning to take my gre in 2023 so I want to know if I will do all videos of your channel can I able to crack my gre with out any coaching??

[@faisalrashid9415]

Hi Philip. For the independent question, why did we not just multiply probability of P occurring 0.3 with probability of Q not occurring 0.6?

[@qt_pi6504]

this is beautiful

[@VishalSingh-cj1pr]

Hi Philip - Thank you so much for posting these videos. These are wayyyyy better than bulk of expensive materials available online. Have a quick query on the question at 47th minute. The answer I am getting is 2%. The probablity of picking a twin could be (pick first from class 1 and then from class two) or (pick first from class 2 and then from class 1) Sceanrio 1: 3/12 x 1/25 or Sceanrio 2: 3/25x 1/12 = 1/100 + 1/100 = 2/100 Please correct me if i am wrong. and thanks again.

[@VishalSingh-cj1pr]

could it be because everytime questions mentions at random, I don't have to consider the order in which they are selected.

[@adeolaadeniran7566]

Hello Phillip, thank you so much for the videos, I’m especially grateful for how to break down difficult concepts 😊. Regarding the first question on calculating opposites (@25:28) why can’t we just multiply 1/4 in four places, instead of calculating opposite and back to subtract from 1? Thank you

[@abhishekkhanna1349]

if u multiple 1/4 in all 4 places that would mean that it is raining on all four days.

[@nikhilt3486]

Hey Philip! Just one query at 21:00 "one of many question", why is 9C3/9C4 wrong solution?

[@palakgupta3116]

Hey Philip! Why aren'y we considering the order in the second unexpected probability trick question? like what if 1st child is selected from the larger class, it is not specified

[@sanarehmat8447]

Hi! As we know that Ets has increase the difficulty level of quant which is unjustified. Sir, you are in a position where people will acknowledge you and support you. Please collaborate with other Gre tutors and specialists to record your protest at this injustice to ETS. Sir, please. Thanks!

[@TheTestedTutor]

I have organised a march

[@sanarehmat8447]

@@TheTestedTutor Hello Phillip! I have asked Mr Saad to speak out against the unfair difficulty level of the Quant section, as well as the overall GRE exam. I mentioned that you are also protesting against this. Today he has a live session with Gmat club. He said he'd mention it in today's session, and he asked me that I should remind you also. You all can collaborate together and protest to ETS against this.. Thanks!

[@Kut_Kut]

Hiii Phillip I just want to say THANK YOUUU🤗 for all these videos. I took the GRE today and it didn’t go as planned, looking to take it again. What advice can you give me to be able to improve my score drastically Looking forward to your reply Thank youuu 🙏🏾❤️

[@TheTestedTutor]

You're welcome! Have you completed my 5 week playlist?

[@Kut_Kut]

Thank you for replying. Yes I did. Excluded one or two videos because of time but I have watched 96% of all your videos.

[@TheTestedTutor]

@@Kut_Kut Have you managed to take and review all 5 ETS tests?

[@bagdad29-0]

Phillip, Thank you for your fantastic content! Currently, I am on the week 5 Quant at your playlist. Suddenly, the playlist changed, and I found the probability part on week four, which was in the week 5 playlist. Don't you think probabilities belong to the week 5 playlist? I am lamenting!

[@TheTestedTutor]

Yes will sort that don't worry. It is because this video now has everything on probability.

[@bagdad29-0]

@@TheTestedTutor Yes!! Great video Indeed. We appreciate your hard work, Brother!

[@krishchowdhary]

Sir Thanks a lot for your really helpful videos but for the last question isn't there a 2% chance in case one you are selecting 3/12 and then 1/25 but in Case 2 we can select 3/25 and then 1/12; therefore either itis case 1 or(+) Case 2, So we add them to get 2/100? Just like we did in the beads question when we had to select either red or Green beads.

[@Manojkumar-dg7tj]

Hi Philip, Apparently the news is that GRE quant difficulty has increased significantly and the official materials do not replicate this. Is it possible to give in better insights as to what is happening

[@mdsajjadali4343]

Hi Philip The 2nd last problem that you did 45:00 about twins, don't we have to do it like the way you did about the green and red beads 14:00

[@shwetaparajuli3868]

I too was thinking exactly the same 😂

[@ameyashirali4371]

What if we have 3 beads will this concept will be applicable on them too?

[@amrithas182]

38:18. Are the options wrong? I don't see any that correspond to the answer 18 percent..should we mark the answer closest to the answer figure?

[@samuelosei-nketiah2130]

Hello Phillip. Excellent video! Although, I am a bit confused about the twins question. Why weren't the ways of picking the siblings considered like in the case of the red and green marbles, please?

[@TheTestedTutor]

Because with the twins you NEED to pick a twin the first time (no twin = fail), and then you NEED to pick that twin's one sibling (which is why you don't multiply by all the twins in the second class). But with the bag you can EITHER pick up red first, then green OR green then red. It is a more flexible situation with more routes to success. It's the same reason we don't count H H (two heads) as different from H H (the same in reverse order). If we need two heads (like a twin pair) then first option must be a head (H), no alternative, no repeat or reversal.

[@samuelosei-nketiah2130]

@@TheTestedTutor Thank you very much. And uh.. wish me good luck!! Thank you.

[@gagandeeparora7727]

Hi Philip! Thank you for this amazing and very helpful video session. Also, I had just one question in the 'Unexpected Probability Trick' at 48:00, Shouldn't we consider both the combinations Picking a Student from First class and then picking from larger class and vice-versa? In case that the probability would be twice of the current answer.

[@theresalouise4077]

It’s what I thought so too. Because they didn’t specify the order of picking the students

[@patsy7514]

Thank you... I was about to ask the same thing. Additionally, don't we have to consider the 'twin 1' OR 'twin 2' OR 'twin 3' when computing the first choice? In your first choice, you can either pick 'twin 1' or 'twin 2' or 'twin 3' in which case the probabilities need to be added.

[@Srg9000]

Hi Philip, thank you for providing great videos! I have a doubt at 38:15 in the independent probability section, the soluton is 0.18 but that doesn't match any of the options

[@TheTestedTutor]

Well spotted ctlr! My mistake, forgot to switch to decimal answer choices. Answer is indeed 0.18!

[@dx5151]

9/50 will be the answer, right?

[@TheTestedTutor]

@@dx5151 as a fraction, yes

[@Srg9000]

@@dx5151 as a fraction, yes, i think the options were from the last question

[@samikshyaaryal9881]

Hey philip! I have a query regarding last question. On computing total we have already divided by 2! to avoid redundancy due to double S then why is it necessary to take 2 choices for the want?

[@TheTestedTutor]

Hey Samikshya, an amazing spot, very well done. 2/120 works or 1/60 (depending on if we adjusted for the 2!) but not 1/30. I have edited the video to simplify. Do check out my Letter Arrangement video for further practice.

[@patsy7514]

48:08 why aren't these independent selections? Why do they have to occur one after the other? Which part of the question gives us this idea? If the selections occur simultaneously, then the answer is 3%. i.e (3/12 * 3/25)

[@JasmineKhamis-un6pb]

Hello Philip! Thank you so much for those videos; they’re nothing short of GOLD! In regards to this video, the Independent question of events P and Q. We concluded the answer 0.18 or 18% as the answer, but it is not one of the answer choices. Is there an additional final step? Or was it merely the wrong set of answer choices?

[@debasismandal1924]

I was wondering the same thing as well.

[@ronakpunase80]

I have a doubt at 38:16, what is the correct answer? The concluded 0.18 does not matches with any of the options, what am I missing?

[@seabasschukwu6988]

thx 4 help m8

[@SathishKumar-23]

I'm really really waiting for this topic. Actually I make this comment befor watch this, but after saw the thumbnail I got self confidence that ok, don't worry about probability. I will nailed it on exam. Wise me luck dude. I'm going to appear on my gre within 10 days..! And thanks for all and everything 💟. Luv from India.#

[@TheTestedTutor]

Best of luck Sathish!

[@dawitkefyalew2618]

how was your result, am going to take it soon ?

[@anishjoshi1999]

love from nepal

[@hemanth_chowdary111]

Hii Sir i practiced all problems in Manhattan 5lb is it enough for gre

[@maameefuamensah]

21:32 I am really confused. why didn't we find Philip x Christina + Christina and Philip like we did with the red and green balls when we found redx green + green x red? What is the difference? Please help

[@rujekomacheka6393]

Hello Phillip, So what is the answer at 38:12 Phillip? The explanation there is not clear.

[@gerardtyson2274]

37:00 can also use complementary rule (1 - 0.4 = 0.6) then do 0.6 * 0.3 = 0.18.

[@reinhmr]

Yeah, but 0.18 is not an answer choice and none of the given answers corresponds to it. In fractional form 0.18 would be 9/50, no?

[@gerardtyson2274]

@@reinhmr ​ in other comments on this video, the uploader has confirmed that the corresponding answer choices he posted for that question aren’t the correct ones. 0.18 is still the correct answer. If you scroll down to older comments posted 8 months ago (at the time I’m writing this) you should find it. Such comments reference time stamps around the 37 or 38 minute mark.

[@reinhmr]

@@gerardtyson2274 Thanks, Gerard. I should have read the whole thread before commenting. Great video, btw.

[@ryanmwaniki6266]

Pls answe this question. Why do we multiply when the question says And? I don't understand why

[@praggo2841]

Hi Philip! I was asked a question on Probability Distribution on my GRE last week. It goes something like this - A set of values of X and their corresponding P(X) were given. Similarly, a certain set of values of Y and P(Y) was given. Question asked - Quantity A Quantity B X Y I had no idea how to solve this. Could you please help with this. I know I don't remember values but a hint would be great!

[@AmarachiKonyeaso]

I think the answer is D. The information doesn’t seem sufficient enough

[@reinhmr]

At 37.44, you give the answer that the probability of P not Q as 0.18. But the answer choices are in fractions, not decimals and none of the answer choices represents 0.18, which is fractional form would be 9/50, no?

[@amrithas182]

At 48:10 shouldn't we consider two different cases of either the first twin was taken from class with 12 students and also the case where first twin was taken from a class of 25 students? Why did we only consider one case?

[@williammcglone6515]

I was thinking the same thing, which is why i thought the answer was 2%... help Phillip! @TheTestedTutor

[@fashionstyle12346]

hey im really confused why you didnt simply use the combinations formula for some questions?

[@raining3110]

Hi philip, for the question at 38:17 on independent, can't one just get the answer fairly quickly by using the probability of p happening which is 3/10 times q not happening witch is 6/10, and that would be 18/100?

[@TheTestedTutor]

But that's just p only happening. What about q only?

[@raining3110]

@@TheTestedTutor Thanks for the reply philip! I actually took the GRE today, your math tutorials have helped me get 166 in quant in the first try. You are awesome!

[@TheTestedTutor]

@@raining3110 amazing! Well done

[@trisha.sarkar]

Hey Phillip, in one of many - if Phillip and Christina are picked, wouldn't we consider both orders P C and C P? How do we know we don't need the orders?

[@TheTestedTutor]

Doing the orders will work and get the same answer but there are so many, like CPNN, PCNN, etc that it is simpler to do the shortcut of just multiplying as shown.

[@trisha.sarkar]

@@TheTestedTutor thanks! Is there a specific trick to identify one of many questions ?

[@temptemp4106]

Hi Philip, Thank you for your videos, they are very helpful. I wanted your help to get more clarity in disguised venn diagram question. It asks for probability of exactly one event occurring. I tried the following - P (Exactly one event occuring) = P( A occurring AND B not occuring) Or P ( A not occurring AND B occuring) = [0.4 x (1-0.5)] + [(1-0.4) x 0.5] = (0.4 x 0.5) + (0.6 x 0.5) = 0.2 + 0.3 = 0.5 ( i.e., 50% option E) I am not able to understand where I am making mistake. If anyone else can point out the mistake, please help.

[@bienvenidos9360]

The probability of B not occurring = 10% chance that only A occurs + 40% that neither event happens. Similarly the probability of A not occurring = 20% chance that only B occurs + 40% that neither occurs. So you're including portions of A and B again in your total. So the probability of only A =( probability that B or the probability that neither event occurs) not occuring = 1 - (.50 + .40) = 0.10 The probability of only B =( probability of A or the probability that neither occurs ) not occurring= 1 - (.4 + .4) = 0.20 So the probability of only A or only B = the sum of these amounts. 0.10 + 0.20 = 0.30

[@bikasbasnet9907]

for 3rd questons( 3P2+5p2)/8p2

[@jineshjain3716]

Probability: 31:00, 33:00 (Independent Prob), 39:00, 50:00

[@bikasbasnet9907]

for 2nd questions we can solve all the questions using counting techniques say p= 5P2/8P2? 20/56

[@VedankPande]

For the first question in the disguised venn diagram section, why doesn't A(1-B) + B(1-A) work?

[@bienvenidos9360]

1-B includes a portion of event A. Similarly 1-A includes a portion of event B. So you're including extra portions of both A and B in your final total.

[@azherhussain3562]

Hi Philip, will we not be tested on mutually exclusive events on the GRE? Thanks for the video otherwise it helped in clearing a lot of my doubts.

[@TheTestedTutor]

That's more of a Venn diagram question...

[@azherhussain3562]

@@TheTestedTutor Thanks for clearing that up.

[@bikasbasnet9907]

for 3rd questions P= 5P1*3P1/8P2

[@bibifatemalipe8895]

❤

[@lapocalosci9963]

What’s the answer for the question at: 38:16?

[@TheTestedTutor]

0.18 but as I wrote in comments the answer choices do not reflect that

[@subashlamichhane184]

In question selecting twin from different class. (Twin from 12c and then twin from 25c or twin from 25c and then 12c ) is not approach.

[@AchiragChiragg]

Doesn't matter. Both will give the same answer