In the question of the Shopping Mall escalator floor 1 to 5: I expected another approach which would be realizing that the speeds under the given conditions are always in AP (M+E, M, M-E), so the time taken under the circumstances will be in HP and the answer will be the harmonic mean of the given time values.

@akshaychavan4673

2 жыл бұрын

You are right we get same answer by that approach

@rishiagrahari4212

2 жыл бұрын

Yes.

@venumohan5500

Жыл бұрын

@@akshaychavan4673 how can we know that the speeds are in AP?

@user-go9hf6dw6d

Жыл бұрын

even in the last question the HP method could be used?

@vamsi565

Жыл бұрын

​@@venumohan5500from info given in question it is of the form---m-e,m,m+e (a.p) Refer previous video(7th part)

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@pavithran5515

3 жыл бұрын

Hi bro can i know ur cat score??

@prasanavarshan9400

Жыл бұрын

@@pavithran5515 100000

Ravi Sir is the saviour for all of us! Please dont forget to like all his videos as and when you play them!

Thank you so much Sir.. You don't know how relieved I am .. I always felt uneasy in this topic..But now I am confident about getting it right

Thank you sir for all the hardwork you have done for all of us.

In last ques n=15 b took 8 step so remaining steps are 7 which are taken by escalator so It will be e*tb=7 Similarly for c remaining steps are 10 So e*tc=10 By equating we get tb:tc=7:10

Thank you so much sir for clearing the concept 👍👍

Best very best ...I am already taking coaching bhit still I came around your vedio and find very very much helpful...after spending 50 k in coaching center its wast of money ...your explanation is best

@shubhamsehgal1131

3 жыл бұрын

I Like how your channel name is You as after reading your comment I felt that I did the same mistake as well.

Thank you sir for all the efforts. 🙏

Alternate way to solve Q1: Speed of P in case 1 = 25 steps / 30 sec = 5/6 steps/sec Speed of escalator = e (let) Thus, (5/6 + e)x(30) = N [speed x time = dist] Speed of P in case 2 = 5/2 steps/sec (since it is tripled) So: (5/2 + e)x(18) = N Equate and solve for e….. turns out e = 5/3 steps/sec Put e in any one of the above 2 eqns to get N = 75 steps.

It was very help full sir keep going

for the second question i am getting answer by applying AP and HP method

Sir, Very nice concept ❤️

Hi Sir, I have a doubt. In the last question, why have we not considered the relative speed (x-e) but just x when put it equal to (10/ta) in A white moving up or down for that matter?

Sir.....! Thank you so very much❤

While taking time which is distance/speed, the speed we have to consider will be relative speed or A's speed alone?

Although the last question was a little challenging, I was able to solve that on my own. Thanks Ravi Sir for explaining this concept so nicely.

@NiaraKamath

15 күн бұрын

In the last question how come the value came 5/3x? The denominators weren't same sir. It was 2x and 3x. Pls somebody ans my query

@dontstanseventeenthenurmis1629

6 күн бұрын

By applying cross multiplication or LCM method​@@NiaraKamath

in second question time is in hp we can easily solve using hp formula aslo

Thank you sir for videos .

if N is no of step when it is switched off then why do we write the equation of N = no of man step + escalator step. Logically it shouldn't be this then ?

The shopping mall question could have been done in 2s by HP concept

@niloychakravorty3832

3 жыл бұрын

Hey ! I was trying the same thing, yet failed. Would you share the solution using the hp concept ?

@avinash85940

3 жыл бұрын

@@niloychakravorty3832 M+E ,M ,M-E are the speeds and they are in AP., therefore their time is in HP . now T {M+E}= 36 T{M-E} = 108 , Therefore T{M} = 2*36*108 / 36+108 = 54

@niloychakravorty3832

3 жыл бұрын

Thank you so much @avinash.

@atharvachoudhary6974

3 жыл бұрын

The H.P concept has made all these problems a piece of cake, I would earlier try to use relative speeds and then stare at my notebook looking to reduce that one extra variable.

@saurabhtiwari4690

2 жыл бұрын

can u tell me how ?

In Some videos u have talked about the quizzes can u plz tell me where can i find them ??

Thank you so much SIR

nice good concepts sir

GREAT VIDEO

Solved the 5:57 question by AP & HP method, Speed can be considered M+E, M, M-E for time 36sec, ? , 108sec , since speeds are in AP, time will be in HP so the time when escalator is not moving can be calculated by b=2ac/a+c . Answer is also same (54secs) is this also correct?

@Rodha

Жыл бұрын

Yes CORRECT

@ss590

11 ай бұрын

Thankyou 💜 so much sir 🙏🏻

@eceb139perurisambasivasrid3

10 ай бұрын

how do u got those 36,108?

Thank you sir .

Thankyou,sir.

thank you sir🙏

Thanku sir

2nd question can also be solved by AM HM concept easily

In shopping mall question if we use AP, HP concept ,we can solve that question within 1 min.

For last question...I took hp of A which gives no of steps...

HP wala funda is way quicker than equating for some question.

Thanks uhh sir jii❤❤❤❤❤

17:47 how much steps will taken by b ? I did like this Steps taken by A =25+25E/3 and B=20+10E by solving this i am getting E= 11/3 and putting 11/3 in equation of A giving 50 steps but B giving 56.66 steps . But according to sir if you will put the value in b you are getting same steps.? How

@heatmuzik1258

Ай бұрын

YOU HAVE CALCULATED WRONG IT WILL NOT COME 11/3

In the question with A and B moving together, A takes 25 steps to reach the top while B takes only 20. But we have taken speed as A= 3x/second and B=2x per . Ideally, higher is the speed, time taken should be lesser right? Is this the right approach?

@swatibisht4572

4 жыл бұрын

Yes, the approach is right. The case you have mentioned is when 'D' is constant, here the distance or steps taken by A and B are different. So, when escalator is switched off N(A)= 50 and N(B)= 60 which means B would have already taken 10 steps before A walked up in escalator that's why even though their steps ratio was 3:2 B reached early to the top. Not given that they walked up on escalator together. hope this ans will help you.

@jahnavijayaprakash9643

4 жыл бұрын

@@swatibisht4572 oh. Clear now! :) Thanks a ton

@swatibisht4572

4 жыл бұрын

@@jahnavijayaprakash9643 ☺️

@scantrace9646

Жыл бұрын

@@swatibisht4572 N = 50 for both A and B. (From your comment, N(B)=60 is incorrect.) Therefore, B did not get a head start. Even if 'D' is constant and they start together, the person with higher speed (A in this case) will always climb more steps. E.g. A → 3 steps/sec B → 2 steps/sec E --> 1 step/sec (constant, same for both A and B) N = Time x Effective speed (A+E or B+E) A x Time for A = Steps covered by A B x Time for B= Steps covered by B E x Time for A or B = Steps covered by E with A or B Substitute any value of D (i.e., Number of steps), e.g., N = 12, 24, 48 etc, the number of steps taken by A will always be greater than B (even though time taken by A to reach the top will be less) because speed of A is greater than B, and E is same for both of them. The confusion arises if you misinterpret 3 steps/sec as 1 hop for A. (And 2 steps/sec as 1 hop for B) Ofcourse, if we were to consider hops, A will hop fewer times than B to reach the top. But if we consider steps/sec, 3 steps/sec literally and mathematically means the person has climbed 3 steps in 1 sec (even though A might have skipped 2 steps and hopped onto the 3rd step).

Q2. Can be solved with HM formula

Why speed of a is taken as 3x?

Rodha is the Zerodha in CAT preparation!

e/x in last question will be 1. 30-10=20

@bharatibharati5260

4 жыл бұрын

No yaar it's 1/2

@15:27 , can the ratio of time also be taken as 2:3 to solve the ques?

@vidyasagarpalakodeti8263

2 жыл бұрын

No because distance covered by them is not constant, we can use that only when D is const

Why Cant we just take time as inverse of speeds like speed is in ratio 3:2 then time should be in ratio 2:3 in second last question?

@wonderwoman2949

3 жыл бұрын

Because distance is not constant. While the Total distance i.e.the no.of steps on escalator is constant, individually A and B don't cover equal distances

9:48 10:36 ⭐

In 15:51, You have multiplied time taken by A to speed of escalator. I can't understand this

@shubhamthakkar4476

Ай бұрын

If the speed of escalator is not given we take with time given multiple by E but here time is also not given that's why we have 25/3x

In the second last question, where A and B are moving up escalator why have we taken their speed to be 3x:2x. Why do we require x when we know the exact quantity?

@dheerajkumar5642

3 жыл бұрын

If you listen carefully , 3:2 is tge ratio of speeds not the speed themselves so 3x and 2x .

@wonderwoman2949

3 жыл бұрын

A takes 3 steps for every 2 of B's steps which means if B takes 4 steps, A will take 6 steps and similarly if B 6 steps then A 9 steps. So we only know their ratio not the actual values.

Sir , shopping complex 1st to 5th question , can we just use harmonic mean thingy

@rajdeepsiddhanta5054

4 жыл бұрын

Yes

@kunalsingh6423

4 жыл бұрын

Can u please tell how ?

@pranavparashar8088

4 жыл бұрын

@@kunalsingh6423 Instead of using Harmonic you can go with AP method by using effective speed funda. Take speeds as M/36 +1, M/t , M/108-1. These three speeds are in AP. Calculate difference between M/36-1 and M/108-1 and divide it by 2. Add this difference to M/108 -1 and equate to M/t. You will get 54 seconds.

@malayswarnkar2261

4 жыл бұрын

@@kunalsingh6423 3 speeds - M+E, M, M-E are in A.P. since their common difference is E. Therefore, the time taken will be in HP. So, the HM of the 3 quantities will be - 2ab/a+b. Solve and you'll get the answer. All the best

@suyashtripathi3842

4 жыл бұрын

Yes

Is there any other method of solving the last question. I am bit confused in the last question..

@Rodha

2 жыл бұрын

Its good. Learn this.

40/x kaise??

Please help with this question sir Pavan walked up a descending escalator (a moving staircase) and took 154 steps in 100 seconds to reach the top. Rishabh started simultaneously from the top and taking 3 steps for every 4 taken by Pavan, reached the bottom in 40 seconds. How many steps from the bottom were Pavan and Rishabh, when they crossed each other?

@noonecaresworkharder1730

Жыл бұрын

Total steps = N Speed of escalator = e ratio of PAWAN Speed to ratio of RISHAB'S is 4:3 SAY Pawan's speed = 4x Rishab's speed = 3x Overall effective time taken for total steps 'N': Case 1: (Pawan and escalator in opp. direction) N/(4x - e) =100 ...1 (Pawan- upwards) Case 2: (Rishab and escalator in same. direction) N/(3x+e) = 40 .....2 (Rishab- downwards) we know Pawan took 100s to take 154steps ...hence pawan speed,4x = 154/100 x =77/200 Solving 1 and 2 by x value, we get N = 77 and e = 77/100 they will cross each other after (total distance /individual speeds) secs i.e., 77/(4x+3x) seconds, i.e., 200/7 seconds Number of steps from bottom = (4x-e) *200/7 = 22 steps Number of steps from top = (3x + e) *200/7 = 55 steps

QUANTS me prob he , rodha sir like aa javo sikhaa dunga >>>

Sir, 17:40 why the RATIO OF a:b is not = 2:3 ?

@aayushdeo9143

3 жыл бұрын

When A takes 3 steps B takes 2 steps A- 3steps ; B- 2steps A- 6steps; B- 4steps . . . . .

@pritheshnarang2166

3 жыл бұрын

@@aayushdeo9143 I'm also saying the same thing 3 steps of A = 2 steps of B. Therefore A/B = 2/3

@shubhamsehgal1131

3 жыл бұрын

@@pritheshnarang2166 I think you are not applying ratios correctly, here we are looking for the speed ratios of A & B.

In the second last question how come the value came 5/3x? The denominators weren't same sir. It was 2x and 3x. Pls somebody ans my query

@harshitaggarwal1053

2 күн бұрын

take lcm

Thankyou sir

How 25/3xE-20/2xE =5/3xE🤨🤨???

@vrushaliharale5026

6 ай бұрын

Same doubt

@harshitaggarwal1053

2 күн бұрын

@@vrushaliharale5026 take E common and then solve the inner bracket by taking lcm

Sir.....last Question me ik ratio nikala hai yeslea tb & tc consider kia hai......but sir agar ( 8 / tb ) & ( 5/ tc ) lekar solve karne par mera answer same ni aa raha......mujhe bas reason jaana tha aisa kyu ho raha hai 😭

@sertnation9605

11 ай бұрын

damn, same

@sertnation9605

11 ай бұрын

nvm I got it. Inke steps same nahi hai B ke 8 and C ke 5. THerefore, Distance is not contant, hence if speed is 16:7, time cannot be 7:16. For time of B, divide no of steps(8) by speed (16) and same for C. The answer will be 7:10

Sir for the last question, tb:tc is 7:16 not 7:10, I even checked the answer, 7:16 is the crct one.....

@youknowwho6366

4 жыл бұрын

Explain how?

@shreyamishra5447

4 жыл бұрын

Ya, 7:10 is actually the ratio of the number of steps taken by escalator in B and C's case.

@arunadityarajjain1129

3 жыл бұрын

@@shreyamishra5447 Both ratio would be equal to 7 : 10 beause speed of the escalator is constant.

@Rodha

3 жыл бұрын

No. Answer is 7:10

@yashjoshi3488

3 жыл бұрын

7:16 is the ratio of speed taken by C and B, 7:10 is the ratio of time taken by B and C.

last question is not good for my brain

Sir video lectures are very helpful..thankyou so much for clearing our concepts But can you just change or mute the starting sound of the lectures ,it is very much annoying while using the earphones.

@arunadityarajjain1129

3 жыл бұрын

or you can just mute it for 30 seconds or skip it!

@sitanmay03

3 жыл бұрын

Like realllyyy?? xD

@aeditspsd

2 жыл бұрын

Banda apna intro bhi na chalaye? 😂