For train ques we can also do it like, Cat runs 3 unit for every x units of Train, Then if cat runs 5 units, train will travel x+8 units. Take ratio 3/5 = x/x+8 3(x+8) = 5x 2x = 24 X= 12 units. C:T = 3:12 = 1:4
For the second last question,time taken for the man to walk both ways: W+B=5hrs 45mins 2B=3hrs 45mins--- equation 1 Therefore, (W+B)*2=(5hrs 45mins)*2 which equals to 2W+2B=10hrs 90 mins --- equation 2 Subtracting 1 from 2 2W+2B=10hrs 90 mins 2B=3hrs 45mins ---------------------------------------- 2W = 7hrs 45mins That's just my approach
W+R =5h45 min If he ride bike in Both ways will decrease 2 hours(gain 2hrs) of his time. Already in W+R=5h45min he gained 1 hour( for both sides he would gain 2hrs , 1 side 1 hour) If he travels both ways by walk it will take 6h45 min 🤔🤔🤔 And if he ride both sides by bike it will take 4h45min (2h gained by riding both side).
Thankyou very much sir, I took a coaching last year for CAT which costed around 38000, and it helped me to get interview call from CAP IIMs, but I was not happy with my performance. So I chose to self prepare, Your channel has proven to be a boon to me, I am now able to notice the knowledge gaps and reason behind my underperformance. The content, the detailed solutions, the method of explaining . All are Awesome. Thanks for making the content free sir. All the best and I wish this channel grows Tremendously in the future.
After 2 hrs A distance is 160 km , B speed diff. is 16 km , it will take 10 hours to overatke the car, So Distance is 960 km, C will take 8 hrs, hence it will start after 4 hrs after A. A =12 hr , B=10 hr , c=8 hr (Total time for journey by A, B, C)
Roman Saini(The Founder of Unacademy) once said: Jo log aapko apne swarth se upr uthkar padhayenge aise teacher aapne dhundne chahiye And Ravi Prakash Sir is Good Example of that They have created these videos with so much effort in it and that too Free
for bike and walk question When 1 bike is replaced by 1 walk (diff) = 2hrs, therefore, when 2 bikes are replaced by 2 walks the difference would be = 4 hrs hence, walk + walk will be 4hrs extra to that of bike W+W = (B+B) + 4hrs W+W = 7hrs 45 min
Ravi sir doing 3-3 za and 5-5 za at 5.45 - 5.50.....haha kitna bhi speed maths seekhlo, this is the best ways to solve multiplication and division. :-P
W+R =5h45 min If he ride bike in Both ways will decrease 2 hours(gain 2hrs) of his time. Already in W+R=5h45min he gained 1 hour( for both sides he would gain 2hrs , 1 side 1 hour) If he travels both ways by walk it will take 6h45 min 🤔🤔🤔 And if he ride both sides by bike it will take 4h45min (2h gained by riding both side).
Thank you for these amazing lectures sir ❤❤ I am cleaning my concept from your lecture and practicing from Arun Sharma book. If i convert my dream college, whole credit will go to you❤ I will appear in CAT 2024.
i have arun sharma but i still havent practiced from it, after watching sir's video are you able to solve the arun sharma problems ? i mean are the questions of same level?
For better clarity wrt tunnel question Train is at distance 'y' from the start of the tunnel and length of the tunnel is x ( AB ) Case 1 : Meeting at beginning of the tunnel [y/S (Train)] = [{3x/8}/ S ( Cat )] Case 2 : Meeting at the end of the tunnel [(y+x)/ S ( Train)] = [{5x/8}/ S (Cat )] Solve both the above equations 2y=3x ===> y=(3x/2) We need for 3x/4 ====> y/4 Ratio : 4:1
But i think that 6 p.m. is not the hours taken for the travel. Hence it cannot be taken as time in the speed time formula. Had the question said that he started travelling from 12 p.m. we could have taken the time travelled as 6 hours.
Is train & cat question it should be 4:1 not 1:4 Because in ques it's ask about speed of train to speed of cat. Not cat to train and obviously train is faster than cat so it should be train which is 4
In time by walking and bike problem 19:45 , Assume time by walking one way as Tw and biking one way as Tb, then Tw+tb = 5 hrs 45 mins = 5(3/4)(Read this as a mixed fraction) = 23/4 hrs 2Tb - (Tw+Tb) = 2 hrs => 2Tb - 23/4 = 2 => Tb = 31/8 Hence, Tw = 23/4 - 31/8 = 15/8 2Tw = 15/4 = 3(3/4) = 3 hrs and 45 mins.
In the walking and riding problem, in 5hr 45mins riding time is also involved so shouldn't we solve for 1riding time and subtracting it by the walking and riding time before we add 2hours to the walking time
Easier explanation would be , Instead of walk and ride , just compare ride - So if both side riding takes 3hr 45 mins and if we replace 1 ride with 1 walk we gain 2 hrs. So if we again replace second ride with walk we would gain another 2 hr . Thus - 3 hr 45 mins + 2hr + 2hr = 7 hr 45 mins .
These doubts make me so confused If at 40 km/h he reaches at 7pm and so to reach at 5pm. From 7 PM to 5pm time decreased by 2/7 times so speed should increase by 2/5 times from 40km/hr and it should be 40*7/5=280/5 km/hr but why is it not 600/13 km/hr plzz explain I m really confused as distance is constant and time is inversely proportional to speed
Sir in previous video question related to scooter speed we add time of both speed as 4+25=29hr and in this video in question reach office at 6pm and 2pm you have subtract the time 3-1=2hr why?? How should we know that we have to subtract or add time ???
At some places you are taking time difference for assumed distance and at some places you're adding time for assumed distance .. How to know what to do and when
it depends upon the question ,in 2nd question for example the speeds are 12 and 15 kmph and they reach at 11pm and 9m respectively. with 180 km distance (which got by lcm) we get t=15 hr (1st case) t= 12 hr (2nd case) here sir has took difference beacuse, to reach at 10 pm which is median of 11pm and 9pm if you add the times 15 hr + 12 hr =27 hr it doesnt make any sense .we have to think logically case by case.
for one of the videos in the TSD series which involved a man and his daughter who picks her up from school , we noticed that he saved a total of 15 mins we divide that 15 mins into 2 parts 7.5 mins and 7.5 mins for going to and fro, but for this question involving riding bike and walking why cant we divide the 2 hours saved into 1 hours while going and 1 hour while coming ? if we do that we get 6 hrs and 45 min. Please explain why this method is wrong ?
In both cases he is returning from his bike only...so how can we take 1 hrs for both ways?....if he uses bike instead of walking then only he is saving 2 hrs
The train in the last question is Balakrishna😂(Tollywood followers can decode it). Jokes apart, this is a wonderful video with the simplest explanations
Sir, how should we know that in particular question i should go with AP or HP approach. I mean to say that how should i identify that this problem could be solved by using AP Or HP approach?
Yes.. You Are right.. Here in last que we write ans is.. Speed of cat to train = 1:4 ..then inverse of it become 4:1 is ratio of speed of train to cat...as you say.. ✌
For train ques we can also do it like,
Cat runs 3 unit for every x units of Train,
Then if cat runs 5 units, train will travel x+8 units.
Take ratio
3/5 = x/x+8
3(x+8) = 5x
2x = 24
X= 12 units.
C:T = 3:12 = 1:4
yes
yes
Did with the same mwthod😊
On what basis are we taking the ratio though
@@AryanKhannaX Cat runs 3 unit when train travels x unit. Cat runs 5 unit when train travels (x+8) unit. So, 3/5 = x(x+8).
Awesome, last question explanation was lit. I am already feeling sorry for 7 people who dislike this type of content.
I'm also ✨bro
ruclips.net/video/TuSz8777COo/видео.html
@@16psycheee ruclips.net/video/TuSz8777COo/видео.html
They must be sir’s competitors 😂
For the second last question,time taken for the man to walk both ways:
W+B=5hrs 45mins
2B=3hrs 45mins--- equation 1
Therefore,
(W+B)*2=(5hrs 45mins)*2 which equals to 2W+2B=10hrs 90 mins --- equation 2
Subtracting 1 from 2
2W+2B=10hrs 90 mins
2B=3hrs 45mins
----------------------------------------
2W = 7hrs 45mins
That's just my approach
W+R =5h45 min
If he ride bike in Both ways will decrease 2 hours(gain 2hrs) of his time.
Already in W+R=5h45min he gained 1 hour( for both sides he would gain 2hrs , 1 side 1 hour)
If he travels both ways by walk it will take 6h45 min 🤔🤔🤔
And if he ride both sides by bike it will take 4h45min (2h gained by riding both side).
Thankyou very much sir, I took a coaching last year for CAT which costed around 38000, and it helped me to get interview call from CAP IIMs, but I was not happy with my performance. So I chose to self prepare, Your channel has proven to be a boon to me, I am now able to notice the knowledge gaps and reason behind my underperformance.
The content, the detailed solutions, the method of explaining . All are Awesome.
Thanks for making the content free sir. All the best and I wish this channel grows Tremendously in the future.
What was ur percentile
@@kazhikkaam2942 95.67
in Train problem:
3:x
5:x+8..... so x=12
Hence,... for situation one, D= 3:12 .....so S also = 1:4
How u can say x=12 directly?
@@satishchodisetti7896 equate the ratios. 3/5=x/x+8 , 2X=24 I e. X=12
ruclips.net/video/TuSz8777COo/видео.html
After 2 hrs A distance is 160 km , B speed diff. is 16 km , it will take 10 hours to overatke the car, So Distance is 960 km, C will take 8 hrs, hence it will start after 4 hrs after A. A =12 hr , B=10 hr , c=8 hr (Total time for journey by A, B, C)
Absolutely top class content available for free. You are doing a tremendous job Sir. Very commendable. ❤❤
The way you explain concepts is just amazing. Thanks a lot Sir
Hats off to sir for explaining each and every topic in such a simpler way ✨
ruclips.net/video/TuSz8777COo/видео.html
Roman Saini(The Founder of Unacademy) once said: Jo log aapko apne swarth se upr uthkar padhayenge aise teacher aapne dhundne chahiye
And Ravi Prakash Sir is Good Example of
that
They have created these videos with so much effort in it and that too Free
for bike and walk question
When 1 bike is replaced by 1 walk (diff) = 2hrs,
therefore, when 2 bikes are replaced by 2 walks the difference would be = 4 hrs
hence, walk + walk will be 4hrs extra to that of bike
W+W = (B+B) + 4hrs
W+W = 7hrs 45 min
Ravi sir doing 3-3 za and 5-5 za at 5.45 - 5.50.....haha kitna bhi speed maths seekhlo, this is the best ways to solve multiplication and division. :-P
d=d
60(14-x)=40(19-x) [Converted time into 24 hour format]
x=4, Which is 4 AM
d=d
40x15 =Sx13
S=600/13 Ans.
Last question's ratio, SC:ST = 1:4
And in real life, marks required for selection, General:SC:ST = 69:4:1
Lol😂
Done 👍🏻
16 September 2024
last Q. Train whistles from 3/2 of length of tunnel from point A
Is this your first attempt at upsc?
Another video with soo much brilliant concepts .,,❣❣🙏🏻
Man you are a piece of gem!
ruclips.net/video/TuSz8777COo/видео.html
great explanation sir cant tell you how much we are getting from your content, thanks a lot for this
W+R =5h45 min
If he ride bike in Both ways will decrease 2 hours(gain 2hrs) of his time.
Already in W+R=5h45min he gained 1 hour( for both sides he would gain 2hrs , 1 side 1 hour)
If he travels both ways by walk it will take 6h45 min 🤔🤔🤔
And if he ride both sides by bike it will take 4h45min (2h gained by riding both side).
Thank you for these amazing lectures sir ❤❤
I am cleaning my concept from your lecture and practicing from Arun Sharma book.
If i convert my dream college, whole credit will go to you❤
I will appear in CAT 2024.
i have arun sharma but i still havent practiced from it, after watching sir's video are you able to solve the arun sharma problems ? i mean are the questions of same level?
In LCM method we sometimes add the hours and some time take difference why and when to use each method please clarify
My fav teacher❤️
for last ques - Vt = speed of train, Vc = speed of cat, when moving towards entrance, Vt+Vc=3d/8, when exit, Vt+Vc=5d/8, solve u get Vt/Vc=1/4
For better clarity wrt tunnel question
Train is at distance 'y' from the start of the tunnel and length of the tunnel is x ( AB )
Case 1 : Meeting at beginning of the tunnel
[y/S (Train)] = [{3x/8}/ S ( Cat )]
Case 2 : Meeting at the end of the tunnel
[(y+x)/ S ( Train)] = [{5x/8}/ S (Cat )]
Solve both the above equations
2y=3x ===> y=(3x/2)
We need for 3x/4 ====> y/4
Ratio : 4:1
3rd question can easily be done by difference in the ratio of time and speed and using distance = speed/time
In 3rd question we can directly get the answer by applying the formula of Distance=Speed x Time
20x6=120
60x2=120
But i think that 6 p.m. is not the hours taken for the travel. Hence it cannot be taken as time in the speed time formula. Had the question said that he started travelling from 12 p.m. we could have taken the time travelled as 6 hours.
Fantastic concept 👌
Cat and the Train question is amazing, improves visualization *
Thank you so much sir for these series. Your explanation easly understood.✨
Is train & cat question it should be 4:1 not 1:4 Because in ques it's ask about speed of train to speed of cat.
Not cat to train and obviously train is faster than cat so it should be train which is 4
For the last question the speed ratio should be reversed i.e 4:1
No
@@aimwbcs5272 He is correct. It should be 4:1 in terms of the qn asked
In the first question, instead of checking it first, can't we assume speeds are in HP since distances are the same?
Last question was brilliant!
In time by walking and bike problem 19:45 , Assume time by walking one way as Tw and biking one way as Tb, then
Tw+tb = 5 hrs 45 mins = 5(3/4)(Read this as a mixed fraction) = 23/4 hrs
2Tb - (Tw+Tb) = 2 hrs
=> 2Tb - 23/4 = 2
=> Tb = 31/8
Hence, Tw = 23/4 - 31/8 = 15/8
2Tw = 15/4 = 3(3/4) = 3 hrs and 45 mins.
It should be (Tw+Tb) - 2Tb = 2 hrs
=> 2Tb = 23/4 - 2
=> Tb = 15/8
Hence, Tw = 23/4 - 15/8 = 31/8
2Tw = 31/4 = 7 hrs and 45 mins.
Sir how can I know that I has to take difference and the sum of time in ques. where distance is assume as the lcm of speed
ruclips.net/video/ctnMy_4GZXs/видео.html
In Train & Cat question cat will surely catch by the train Hence cat will dead ,
R.I.P. for the cat 😂
hence the answer should be Cannot Be Determined , out of respect for the CAT.
@@karthikmadhusoodanan7274 I see what you did there
In first qsn if speeds were not in hp then how would we solve? Please can someone explain
Thank you so much sir!
In the walking and riding problem, in 5hr 45mins riding time is also involved so shouldn't we solve for 1riding time and subtracting it by the walking and riding time before we add 2hours to the walking time
same doubt, anybody got that?
@@arunadityarajjain1129 You will get the same answer by that also, but the approach by sir is logical and direct hence saves the pain of calculation.
It'll be 6hrs 45 minutes bro
Easier explanation would be , Instead of walk and ride , just compare ride - So if both side riding takes 3hr 45 mins and if we replace 1 ride with 1 walk we gain 2 hrs. So if we again replace second ride with walk we would gain another 2 hr . Thus - 3 hr 45 mins + 2hr + 2hr = 7 hr 45 mins .
Last question is OP 🔥
i really felt proud when i solved the last sum bymyself withpout even touching pen 😀😁(coz i have already seen this somewhere)
These doubts make me so confused
If at 40 km/h he reaches at 7pm and so to reach at 5pm. From 7 PM to 5pm time decreased by 2/7 times so speed should increase by 2/5 times from 40km/hr and it should be 40*7/5=280/5 km/hr but why is it not 600/13 km/hr plzz explain
I m really confused as distance is constant and time is inversely proportional to speed
8:40 time difference is 8 hours, not 4 hours, and the answer will be 240.
Both the times are in pm so the difference is 4 hours not 8.
You haven't mentioned about meeting questions. Just one variety of questions.
Sir relative speed to bahot vast topic h.. U hv covered only in 1 video.. Sir I want to see more of the relative speed concept. Sir pls reply
he has made 5 vid on relative speed
@@shwetak8477 send me link
@@deeptijha861 its in the playlist: ruclips.net/p/PLG4bwc5fquzgfMh4YFDnv7fttM0RIKiUQ
Superrr amazing explanation sir❤❤❤❤❤❤🙏🙏🙏
Btw sir cat was alive or not in the end?
:P think positive
@@Rodha sure sir ❤❤❤❤😊😊😄
hehe😂
You are GOD LEVEL. THANKYOU
Sir in previous video question related to scooter speed we add time of both speed as 4+25=29hr and in this video in question reach office at 6pm and 2pm you have subtract the time 3-1=2hr why?? How should we know that we have to subtract or add time ???
By the question, what we have to find ,in this way
Awesome sir
At some places you are taking time difference for assumed distance and at some places you're adding time for assumed distance ..
How to know what to do and when
Same Issue
it depends upon the question ,in 2nd question for example the speeds are 12 and 15 kmph and they reach at 11pm and 9m respectively.
with 180 km distance (which got by lcm) we get t=15 hr (1st case) t= 12 hr (2nd case)
here sir has took difference beacuse, to reach at 10 pm which is median of 11pm and 9pm if you add the times 15 hr + 12 hr =27 hr it doesnt make any sense .we have to think logically case by case.
u can compare with the 2 nd question of the previous video that is time speed distance 5 th tutorial
In 2nd ques where the speed reqd. to reach office at 10pm, can we calculate that
By speed time ratio
S1/S2 = t2/t1,
15/s2 = 10/9
=13.5??
Those are not the actual times, those are click times. Take t, t+1, t+2
for one of the videos in the TSD series which involved a man and his daughter who picks her up from school , we noticed that he saved a total of 15 mins we divide that 15 mins into 2 parts 7.5 mins and 7.5 mins for going to and fro, but for this question involving riding bike and walking why cant we divide the 2 hours saved into 1 hours while going and 1 hour while coming ? if we do that we get 6 hrs and 45 min. Please explain why this method is wrong ?
In both cases he is returning from his bike only...so how can we take 1 hrs for both ways?....if he uses bike instead of walking then only he is saving 2 hrs
Happy teachers day sir
Tysm sir ❤ upload more videos big fan
The train in the last question is Balakrishna😂(Tollywood followers can decode it). Jokes apart, this is a wonderful video with the simplest explanations
Thank you
Ek daam jhakas🥵🥵
27:37 GOOD CONCEPTS
ruclips.net/video/ctnMy_4GZXs/видео.html
can anyone tell , how to know when to take the time difference and when to sum the assumed time ?
Why we apply that much concept for that time question D=speed ×time is enough na
I guess the answer will be 4:1, not 1:4 as in ques it is asked about the ratio of the speed of train to the speed of a cat.
in the 7pm,2pm office question, if we solve by difference in time taken method the speed comes out to be 360/7 km/hr. is this right or wrong?
Thank uh so much sir
Great!
Sir, how should we know that in particular question i should go with AP or HP approach. I mean to say that how should i identify that this problem could be solved by using AP Or HP approach?
speed will be given for 3 or more than 3 variables
Sir my quant is weak , what can I do ?? For ,pl guide me ..
Thankyou sir 🙏
Fun Hack- Watch at 1.5 speed, its still very understandable. Thank me later
No sir, 1.25x is better
i watch at 2- 2.5 speed..lol
2.5 lol, watch inequality session please :p, upper limit here is 2 😂
@@sanklan10 have you ever heard about "browser extensions " ....LOL
@@sanklan10 dara mat bhai...🥲
The question is asking for ratio of trains speed to cats so ans should be 4:1. Isn't it?? I always get confused on this plz help
Yes.. You Are right.. Here in last que we write ans is.. Speed of cat to train = 1:4 ..then inverse of it become 4:1 is ratio of speed of train to cat...as you say.. ✌
I also got confused
no because in that question relationship is takenj between distance and time which are directly proportonal so ans will be 1:4 only
@@techtalkies4119 vo baat to koi kar hi nhi rha dost
Yes and he has written also SpeedofCAT : SpeedofTRAIN = 1:4 answer is the opposite
The guy in the second last question should ask for home posting. He is travelling too much for work.
They say the cat is still running !
Sir if times is in hp , so speed should be ap. Then how we calculate speed in ap ?? Please tell
What's your question , you want the speed in ap ? if a,b,c is hp in time , then 1/a,1/b,1/c is AP in speed .
Thank You sir
Can u solve q2 in lcm method? If so how?
Thank you, sir.
Rodha community 💚
Maza aa gaya sir
OP ravi sir 🔥🔥
Should not the last one be 4:1 ? Ratio of speed of train to speed of cat?
yes, it is 4:1
This question are hard . To solve every question i need to see the solution 😢
Btw, cats can also climb walls.
Feeling bad for the cat
Fantastic experience
what is meant by isspeed😂
these people really gotta move near their offices
Can anyone help this,
7 pm - 15 hrs = 4 am, how?
Take out 12 hours from 7 pm, you get 7 am. Now subtract 3 hrs more, you get 4 am
"It's a cat question" It sure is 😅
12:29 bro got placement out of country 😂😂😂😂
22:00
the cat di.......😭😭😭😭
24:00
💙💙
Raat me office kya karne jaa raha? In second question 🤔🤔 5:20
'night shift ' kabhi suna hai bhai?;)
Thankyou sir
cat died sad.......
🐈 has 7 lives , u forgot? Idiot?
@@nef_nef idiot u!
Amazing explanation sir! What you are doing for us students is inexplicably brave. 🤌🏼 ✨ I can never stop appreciating you sir. Thankyou very much 🙏💯
Thank you sir.
20:00