Numbers 2 || Number Systems || CAT Preparation 2024 || Quantitative Aptitude

[@rajeshwaribadigerc-1185]

Cat 2026 mark it🎯

[@abhishekpathak1572]

Hi

[@jyotivirat1909]

Hello

[@jaipurvibes3591]

Hello

[@samarth2267]

2025*

[@technicalinfo6094]

Take rest bro

[@avanishsinghchauhan691]

After paying huge pile of money for books and fraud coachings, one is left with only disappointment.... But then Ravi sir with his video of Rodha Channel appears and takes away all the tensions of Quant, Lr, Di,etc and leaves us with full knowledge about each concept..... Thank you sir.... I can miss my coaching classes but never dare to forget watching your video even on a single day💝💝

[@Diabolical3010]

offline coaching at this time? or you're talking about online?

[@shashankpandey1966]

same comment in every video...

[@AARUSHI853]

Kya is playlist m LR DI ki bhi video h?

[@rishabhshukla5893]

Well said A very big thanks to Ravi sir A true legend

[@FlyingNationTrust]

Mai to Mba ki tayyari kar raha tha ab aisa lag raha hai CAT nikal jaye ga .

[@hecker3268]

*Two common doubts:* 1. *Reverse is not true* It means all prime numbers will be of the form 6k+-1. But all numbers which are of the form 6k+-1 are not prime numbers. For example, if you take the prime number 13, it is of the form 6k+-1 ie, (6×2)+1 . But if you choose a random value for k, for example k=4, (6×4)+1 = 25 which is not a prime number. So that's what he means by "reverse is not true" 2. *Odd number question* They are all odd numbers. The equation for odd number is 2k-1. So if we take first term and equate, 2k-1=1, solve, k=1. For the last term, 2k-1=91, solve, k=46

[@premmotghare4887]

25 is a square of 5 so i think it's an exception

[@khyatisrivastava3193]

Thanks for solving

[@akshatgarg8894]

@@premmotghare4887 6*8+1=33 which factors are 3 and 11

[@UCHPANDIYARAJD]

👼🏻

[@theharshsays_1088]

Pls tell me how to decide K

[@oberoiswisdom9589]

His first example is how I did my maths all my life lmao

[@shikshakotwal3896]

Need more teachers like you. This is by far the most useful channel for CAT. I have the study material of TIME and I can say topics are covered in depth in these videos. Thanks a lot, Sir.

[@anchalmehrotra9502]

yes u r right .now i think i have wasted my 55000 in time

[@sudhakarankumar9027]

@@anchalmehrotra9502 😧ayyo ..sad.. Did you purchase study materials?

[@anchalmehrotra9502]

@@sudhakarankumar9027 ha time ka mila tha

[@Techion]

@@anchalmehrotra9502 hi bro, is this enough for ipmat

[@pranavcu5788]

Same I was going through my cat books but couldn't understand any examples of those books so I came looking for explanation of these topics and was lucky enough to find this hidden gem.

[@davalabhashakachoor872]

2 video not understand

[@indiaviralvideos7021]

Sir in question 1+3+5------+ 91? You have taken it in the form of 2k-1 but odd numbers can be in the form of 2k+1 as well. So, can we take k=45 and and square 45. Can you please explain why you have taken it 2k-1 and not 2k+1? Please sir

[@adityatrivedi579]

If we take 2k+1 then the k for 1 will be 0 so to make the first no counted as 1 we have taken 2k-1

[@nandinisatdeve13]

Can you tell how 46 came? I am confused

[@hecker3268]

@@nandinisatdeve13 they are all odd numbers. The equation for odd number is 2k-1. So if we take first term and equate, 2k-1=1, solve, k=1. For the last term, 2k-1=91, solve, k=46

[@HarshSharma-wn4if]

@@adityatrivedi579 Hey can you tell why we can't take k=0

[@kalammalik8998]

sir it means 6k+1 not always prime number but prime nnumber always in the foarm of 6k+-1

[@aadishjain7454]

Exactly

[@poorveebodgal7538]

@@aadishjain7454 No , because in 7/6 Ans is 1 (positive 1) but in 5/6 Ans is -1 (when it is divided by 6 ) or 5 ( when it is not divided by as numerator is smaller so)

[@Lvk2024]

Aaj se mera bhi favorite word "Right" ban gayi :D Thank you sir, I am understanding the concepts very lucidly

[@DollarMohan]

@all , how 11 square + 12 square+....+20 square = (1 square + 2 square+....+20 square) - (1 square + 2 square+....+10 square)

[@AaryaDev-o1u]

Yes I also didn't understand that question

[@beingtheangle3585]

Kon kon sir ke classes 2024 me dekh rha hai ?

[@manzaransari9591]

You are going for cat this year?

[@beingtheangle3585]

@@manzaransari9591 yes but still thinking its not safe to take admission on loan

[@Shagufta_2310]

16:25 sir yhn smjh kse 15 prime no hoga n 25

[@gabarrahul2102]

25 is not a prime number

[@hariharany9195]

Sir, what is the utility of the 6K+1 rule for prime numbers? Where can it be used effectively?

[@srishtiagrawal340]

Are all these videos enough for CAT preparation??please answer

[@ishikajain5621]

Sir concept ke liye aapki sirf KZbin videos sufficient h na teeno sections ke liye?

[@yazhini.s6744]

Thank you sirr🙏we will support u alwayss

[@shalinitripathi5378]

Thankyou from Uttar Pradesh Gorakhpur

[@shanaparveen7573]

I have a doubt .plz someone clear it .In the question 2 of summation part . ques is 11^2 but in soln sir solved it taking 10^2.can anyone tell me why ?

[@naveenkumars4132]

Because the formula is applicable for series starting from 1 so he is considering at first 1-20 and from that subtracting the first 10 terms to get the actual answer.

[@naveenkumars4132]

Preparing for CAT 2021 exams ?

[@tanvikasera6639]

@@naveenkumars4132 thank you so much for explaining this 😁✌️

[@rubinakhan759]

How 2k-1 in the fist sum with 91 as the odd number became 46

[@anjalimali06]

Does anyone know where can we clear our doubts of quant? Any app or website or anything?

[@AashishKumar-km2bd]

Sir how 2kplus1,2kplus3,2kplus5,2kplus7,2kplus9 are 5 consecutive odd numbers plz explain

[@khyatisrivastava3193]

10k + 25 = 5(2k+5) = 5 is the multiple

[@eyaShukla]

Sir I'm starting of my preparation with number system, should I finish all the lecture videos (of number system) to go quizzes or should I carry them on side by side?

[@gayu2905]

Yess I'm a beginner!!! I really find your videos are very useful to us..Thank youu so much sir❤️✨️

[@UBAARUNS]

Also me

[@grandmasters733]

Hi..

[@sn4480]

I'm a fresher as well, are these videos enough for CAT?

[@Shruti_mantry]

Hii kya apke sare rodha KZbin lecture ke notes hai kya please send me

[@Shruti_mantry]

​@@sn4480Hii kya apke sare rodha KZbin lecture ke notes hai kya please send me

[@madhushreebharati4378]

Sir your lecture is really very helpful. Can you please suggest the book for Quantitative Aptitude?

[@LeftBrainLogicalLearning]

R.S. Aggarwal Quantitative Aptitude is the best book..

[@rajsaini4881]

How k =46

[@GamingWorld-vs9ro]

2k-1 here k is the count no, so 2k-1=91, 2k=91+1, 2k=92, then k will be k=92/2=46 which is the odd no count

[@r4hoool]

if u multiply 46 with 2 then u get 92 in which u have to subtract 1 so that it makes 91. basically in the form of 2k-1

[@nimishamall6018]

Thank you so much sir, it's very helpful for us.. Sir one query why odd form no. is true for 2k -1 and not for 2k +1?. Sir, in your ques also 1+3+5+....+91. Here, we are taking 2k-1= 91 Answer is 46 and if, 2k+1= 91 Answer is 45. So we should not consider 2k +1 sir?

[@aroraankita381]

If we are considering 2K+1 then for the first term 2K+1=1,K=0 then counting the 45th term and the 0th term total terms = 46

[@nimishamall6018]

@@aroraankita381 it means we can do with both the forms right?

[@nimishamall6018]

@@aroraankita381 thank you so much..

[@kartikborade3128]

How you calculate K=46 please explain me

[@Ankitmodi140]

2k-1=91 2k=91+1 2k=92 K=92÷2 K=46

[@shivgaming1979]

Summation of even no's after taking 2 as common what will happened I don't understand Please someone tell me

[@ruhulamin7194]

Thank you so much sir u explained beautifully.... Love you sir from Assam

[@vashishtjha1176]

Sir can you explain in hindi?

[@AayushKumar-mj6wb]

Sir why don't you add ppt slides in a folder for downloads. Kudos to you for your great initiative,you way of teaching and content is just amazing.Where all teachers are busy in unacedmy,you are the one who has provided free quality content.

[@rehnumanaqvi7529]

He is also there now

[@GautamSingh-sm4cw]

@@rehnumanaqvi7529 give link?

[@rehnumanaqvi7529]

@@GautamSingh-sm4cw kzbin.info/www/bejne/aaKZnXdrd6lgjZY

[@Shruti_mantry]

​@@rehnumanaqvi7529where is the link to download please share

[@Shruti_mantry]

​@@rehnumanaqvi7529Hii kya apke sare rodha KZbin lecture ke notes hai kya please send me

[@surabhitamrakar4184]

In 1st summation question how we get k=46? Pls answer if anyone knows !

[@Randomworldindia]

Got it ?

[@surabhitamrakar4184]

@@Randomworldindia yes thankyou !

[@Randomworldindia]

@@surabhitamrakar4184 welcome 👻

[@MahimaTrivedi-y8z]

still i can't get 46 kaha se aaya....!!!!! 7:32

[@NopeWope-j7e]

Mujhe bhi samajh nhi aaya ye 46 kese aaya

[@divyamjha8721]

2k-1=91 2k=91+1 2k=92 K=92/2 K=46 Its pretty easy thoo...😉

[@NopeWope-j7e]

Thank you for explaining 😊​@@divyamjha8721

[@divyamjha8721]

@@NopeWope-j7e nevermind brother ✌🏻

[@Ni-ym6uz]

Thankyou bhai​@@divyamjha8721

[@PonnaHemasundar-db6pw]

Cat 2024 preparation Your explaination is super sir

[@kajaltiwari7805]

Sir please help me with how you do fast calculation?...

[@KhushiKumari-ll2ru]

How to get squares of number in 2-3 seconds ?? Where i get that video sir

[@namratasingh5634]

Can someone tell me what he explained in the last minutes about "reverse is not true" Please. It just went above my head

[@sagartewatia8383]

Means all prime no.s are in the form of 6k+-1 but all 6k+-1 are not prime no.s

[@Beginerme]

sir i have a doubt how i can contact you plz guide me sir that would really help me alot sir

[@AtishayJain-ld1zl]

love you i solved a freaking question myself the concept i never got in school i am doing it now for mba you are god

[@harishrangasamy6960]

suppose we have a question for 31 square to 40 square how do we calculate those numbers?

[@rohansarda2696]

(1^2+2^2+.......+40^2)- (1^2+2^2+.....+30^2) Now put the formula for summation of square you will get the answer.

[@tanvikasera6639]

But why will we do that?

[@tanvikasera6639]

Can you please explain

[@tanvikasera6639]

@@rohansarda2696 can you please explain that??

[@anuraggautam8976]

@@tanvikasera6639 for getting the combination of 31^2 to 40^2

[@jigyasanahar2189]

In last method of prime no uh've said "reverse is not possible" what is the meaning of reverse in this concept??

[@anishdhawan8321]

it means if you put any value of your choice in the place of k it won't necessarily give you a prime no

[@sidhant3912]

Take the example of 1001. When divided by 6, the remainder is - 1.but it is not a prime though it satisfies 6k+1. In short every prime no. can be expressed as 6k+1 or 6k-1 but every no. That can be expressed as 6k+1 or - 1 is not a prime no.

[@prernasingh7557]

@@sidhant3912 thank u it helped me a lot😊

[@prakashdesai4126]

Well explained !!! Thank you for your efforts.

[@kirtansahu2178]

AT 7.22 HOW IS IT 46 ?? CAN YOU PLEASE TELL ME ?

[@RvKs-life.values.]

Whats the meaning of reverse is not true...?

[@Mishrajisehorewale0311]

Sir there are students who is starting from the basic

[@lostangles5521]

Yeah I didn't get summation parts how it's starts we need more clarification we started from scratch

[@adrashrgaming7961]

Same bro same

[@Mishrajisehorewale0311]

@@lostangles5521 Exactly

[@companionsak2731]

Sir ye odd no wale questions mei Ap kaise solve Kiya smjnni aya

[@shashankkumar6206]

at 19:05 How 25 is a prime number ? Is that a mistake? Anyone please tell

[@aasritachowdary2144]

he talked about it at the end of the video.

[@dataaccount1699]

How ro check whether 1009 is prome or not??

[@aishwaryadhaigude3460]

As per my understanding, even and odd numbers can be negative, I.e -2, -4, -6 are even numbers and -1,-3, -5 are odd numbers. Could you please share the source which states that even and odd numbers are non-negative?

[@SiddhantVerma-tp1gt]

For this comment I will subscribe you

[@anishchar4282]

You are one of the best teacher ❤️ Thank you very much sir 🙏🏻

[@ashishv1407]

Can someone explain how we come to the equation at 9:15 please?

[@ruchitharaj1515]

It's in the form like we want the sum of 11+12+13+.......+20 so we can get the ans by subtracting summation of 10 by summation of 20 the same is in the square form

[@indrani_jha]

had the same question paused the video for 15 minutes of analysis. we're so bad at basics brother

[@Kkohli]

but 25 is not a prime number.

[@sanyamsinghi1802]

at 22.00 he said that 25 is not a prime number thayswhy he said reverse is not true meaning all prime no. are of the form 6k±1 but all no. of the form 6k±1 are not prime

[@sanyamsinghi1802]

22:00

[@uddhavsrivilasan8460]

Can anyone explain what is meant by "the reverse is not true" when explaining 6k +/- 1?

[@ankursharma-ho2cj]

only one condition is possible either + or - 1

[@BhavoukHCH]

great clarity

[@stewie.griffin.2875]

Why is K = 46 at 7.35

[@rohitbhattiwan1272]

Sir is it true that sum of n consecutive odd numbers is always multiple of n

[@aeditspsd]

The sum of consecutive odd numbers starting from 1 is n2(squared). So, I guess, the answer has to be a multiple of n.

[@vasubansal4154]

Thank you so much sir for your guidance ☺️

[@sameerpratapsinghpara1225]

Sir first of all your lectures are superbly awesome.. I am preparing for ipmat will this video's work ryt...

[@sakthidharshini56]

Sir, is this playlist enough for SSC aptitude ?

[@yuvrajandatul1618]

20sir ye 6k-1 vala smj nhi aara remainder -1or 5 lkaise possible h when 5/6 ---20 min

[@AmitKumar-od1gu]

(5) In 5/6 the quotient is 0. It means the entire no 5 cannot be divided by 6 so the remainder is 5... (-1) In other words we can also say that if the numerator was 6/6 it would easily get divided and remainder would be 0 but it is 5/6 so the remainder is - 1.

[@sanyamsinghi1802]

agr hum 5/6 kre or 6 ones are 6 likhke 5 k niche betha de to 5-6=-1 lekin normal division me hum negative lete nhinh as remainder means what remains thus 5/6 me 6 0s are 0 likhkr remainder 5.

[@divyajain6183]

9:30 why subtract 1 SQUARE 2 SQUARE.......10 SQAURE? CAN SOMEONE EXPLAIN!!!

[@poojareddi162]

Sir I love ur teaching but I didn't understand last one which u have explained that 6k+1...in that whn we divide...by 6...that is if 1/6 ....remainder is 4...nd 6k divided by 6 and the remainder is k...nd how did u get the remainder s...1 nd 0 ...and next one even...6k-1...I have stucked wth these 2... really not only me....I have forwarded to my frnd even he didn't get it... could u please explain for us sir😢

[@anupamayadav7491]

At 7:09 how did u get k=46 for 91 ??

[@r4hoool]

if u multiply 46 with 2 then u get 92 in which u have to subtract 1 so that it makes 91. basically in the form of 2k-1

[@owaowa8442]

@@r4hoool how do u do fast calculation to find out k will be 46

[@bubu.chuche]

@@owaowa8442 see its pretty easy if you put 2k-1=91 you'll get 2k=92 and then k=92/2 which is 2k=46

[@rushikeshkadam3248]

Last question 11 square 2+ 12square 2.......+20square =?

[@Jai14best]

19:04 25 is not prime number

[@abhinandiniborkar2393]

21:53

[@swapnilpriyadarshi8407]

sir im confused in the first question of odd no. i think the no. of odd numbers will be 45 and not 46, as if we go by the formula 2k-1=91 so 2k=90 and l will be 45. please correct me if i'm wrong.

[@aroraankita381]

If we are considering 2K+1 then for the first term 2K+1=1,K=0 then counting the 45th term and the 0th term total terms = 46

[@adrashrgaming7961]

@@aroraankita381 can u explain it me to more clearly I'm confused

[@nandiniverma6049]

Can anyone tell 46 kaha se aya ?plzzzz I don't understand

[@aayushiarya4209]

Jab humne 2k-1=91 Kiya to 2k=91+1 2k= 92 K = 92/2 K = 46

[@nandiniverma6049]

@@aayushiarya4209 thanku so much di ❤️❤️

[@r4hoool]

very helpful concept building video, can't wait for the upcoming journey with Rodha for achieving cat25 :)

[@jatinsingle7743]

11:15 answer will be 2475

[@shanmukhteddu204]

sir can you please share the video link to calculate squares and cubes that you mentioned during the video.

[@vishesholla9983]

22:04 you are saying that reverse is not a prime no ................ BUT 6(5)+1 { where k = 5 , which is a reverse of 6 } = 31 , which is a prime no. .................... & 6k-1 -------- puting k=4 [ which is a reverse no. of 6 ] gives us the answer 23 , which is a prime no. ....... please answer me

[@UB123]

Thank you so much sir 🙏🙏🙏

[@prashant27695]

Thank you Sir Can you please provide pdf link of all the lectures

[@biadbvideo4369]

Thanxx sir for free cat coaching

[@PriyanshuSingh-iy6nj]

Sir I didn't understood the summation of odd numbers.Kindly please explain this to me.

[@tanyasharma9486]

same

[@Aditya.021]

Hm

[@kumarsanjeevcover]

Same i Also didn't got it....

[@pavankumar132]

@@Aditya.021 sum of first two odd numbers is square of 2 same for sum of first 3 odd numbers which is sqaure of 3 so formula is nsquare

[@pavankumar132]

@@kumarsanjeevcover sum of first two odd numbers is square of 2 same for sum of first 3 odd numbers which is sqaure of 3 so formula is nsquare

[@adityathakur2683]

But is this going to work If I place 89 or 84 as the prime number because I don't think they are

[@archanapardeshi104]

I do not understand sir....

[@sajalgupta823]

Sir ek query hh apne bola tha odd ke liye 2k+-1 dono use kr skte hh but in ques apne 2k-1 kiya jisme 2k-1 =92 hh hum 2k+1=92 q nhi apply kr skte isme

[@akashdeepverma2708]

What is answer and how to solve "The sum of first consecutive 5 odd number is 197 ? How to solve it? what is its answer ?

[@mansisukhdeve]

It could be better if you start explaining in hindi....

[@mindspace9161]

what is the meaning of k in 6k+1 ???????????? why you use k frequently

[@ballincoomer42]

8:34

[@anushka3499]

1sq.+2sq.= n(n+1)(2n+1)divide by 6 why these eq.is divivde by 6

[@pratikkotak6765]

In 6:41 46 kese aaya? Please explain anyone

[@Smalltowngirl4136]

2k-1=91 Then 2k=91+1 K=92/2=46

[@pratikkotak6765]

@@Smalltowngirl4136 thankyou so much

[@maruavasar]

hello sir plz KZbin Automatic Caption on kar dijiye

[@Aman-sj1zv]

ek saal bad mene suru kiya ha sir. thanku so much ❤️

[@itisViral-nx7xr]

how to get quizzes and previous year questions solved by rodha

[@dpatel5364]

sir, I have a doubt in prime number form... can't able to understand how to find whether it is prime num or not.....

[@shwetaupadhyay8472]

No one can explain better than you 🙂 😊😊😊

[@dishasingh7482]

Thank you,sir.

[@xgfgcv-xg1cb]

Hey team, why in the 1,3,5,7,9...91 example we could not take 2k + 1 ? and in this representation what is k, how could we equate to 2k-1 =91?

[@tusharpardeshi2115]

You can still do that. But, you would start from 0 and go on till K=45. And you would assume that n=45 and your final answer will be wrong. So, in order to avoid mistakes we take it as 2K-1. . In case you are aware to count 0 to 45 and get n=46, then you can sure use the formula

[@xgfgcv-xg1cb]

@@tusharpardeshi2115 Many Thanks Tushar fo your reply, Yes the total numbers n come out to be 46 in both the cases. It is great to notice that you responded, it actually gives comfort that someone is at the other end. Thank you.

[@aniketsrivastava8237]

Sir in question 1 + 3 + 5+______91 in this k = 1 and how 91 become k =46 please explain this

[@HarshSharma-wn4if]

@@xgfgcv-xg1cb can you tell how u r getting 46 in both cases?

[@Shagufta_2310]

Sir ye prime no smjh ni aya

[@priyasoni637]

In the question 11^2+12^2+13^2+.......n^2 Why we took 1^+2^+...10^2 I didn’t get this

[@tusharpardeshi2115]

Since there is no specific formula for calculation of individual squares starting from 11 upto 20, what Sir did was calculate the sum of individual squares from 1 to 20 using the standard formula and from that he subtracted the squares from 1 to 10 (again using the formula). It gives the same answer. It is just like adding 1 to 20 and subtracting 1 to 10 so that you can get addition of 11 to 20.

[@vibhakumari9584]

@@tusharpardeshi2115 Thank you i had the same query ..

[@befree27]

Sir l had doubt about smallest 4 digit prime number

[@034seca3]

10:50, wtf calculation was that, how did he multiply that

[@twotone_111]

Can someone explain how he came at 46

[@keepgrowing7]

Follow 2k-1 pattern starting with 1 at the end you have to take 46 to satisfy this.

[@avantikabajpai4852]

Just>>>>>

[@Evil-FiGHTER05]

Sir y we taken -(1 square + 2 square + 3 square so on + 10 square

[@AnamikaKumari-id7if]

I do not understand the topic from 4:24 to 11:20 time period plz help me 🙏🙏🙏

[@shailpallavi9641]

Thank you so much sir. Doing a great job for students who are financially weak