Great one… Escalators made easy I must say 🙂
Can you please post few articles on escalators, I mean few more questions with such lucid explanation.
I know there is one more article on the same topic but a few more questions would be like icing on the cake…
I will try 🙂 Right now I don’t have any good questions on the topic (mostly, those I have are similar to those posted already) – if I find some new thoughts to add will surely do so.
Right now PnC is the focus, and I plan to do some Geometry as well in the next fortnight if possible, as I have yet to touch it and Geometry is a popular topic in CAT….
Sir! A doubt.. Please clarify.. I dont know why but I am unable to link this question to the examples you have mentioned in this post and hence finding it tough to answer them-
1. Ram takes 60 seconds on an escalator which is moving down when he walks down but takes 40 seconds when he runs down. He takes 20 steps when he walking whereas he takes 30 steps when he is running. What is the total number of steps in the escalator?
2. Atul and Mahesh are climbing on a moving escalator that is going up. Atul takes 30 steps to reach the top whereas Mahesh takes 32 steps for the same. This happens because Mahesh is faster than Atul. Mahesh takes 4 steps whereas Atul can take only 3 steps in one second. What is the total number of steps in the escalator?
At a rough cut I am getting answers as 50 and 40.
Used a different logic on the first one but I guess the equations should be something like 20 / (x – 20) : 30 / (x-30) = 4 : 9.
Second one should be 30 / (x-30) : 32 / (x-32) = 3 : 4.
Answers are absolutely correct (as expected)..
What logic did you use for the first one?
Escalator in first case travels 60 sec, second time travels 40 sec (2/3rd of that), so x – 30 is 2/3 of x – 20. So x is 50. Hard to explain in writing, kind of intuitive approach….
I wanted to know about the RHS of the equatn i.e 4:9
20 steps in 60 sec v/s 30 steps in 40 sec baba! Take the ratio of speeds.
I recommend, when you find something like this confusing, try and work it out on your own. If you wait till someone gives you the answers you will be habituated to that only and will never learn how to work it out for yourself. Trust me on this.
Thank you sir! Your advice will always be followed.
(n+20)/(n+30)=60/40.Therefore n=50.where n is the no. of steps moved by escalator and is constant whether Ram is running or walking….Nothing but the total distance covered is the same .Same logic as in thief being chased by a police…..
I am not sure what you mean exactly – (a) the number of steps moved by the escalator changes in both cases and (b) the equations you wrote would NOT yield n as 50 anyway.
Catcracker please check my logic is correct or not
in 2nd ques, if we calculate 15 steps of person(G) as to 1/3rd of 45 then, we will be doing the same as 2/3rd of 45 for 2nd person (J), then ans. came out to be 30
so how did you chose the steps of person between 1/3rd of 45 and 1/4th of 60 to arrive at conclusion?
Because the second guy J is faster, he will be climbing for less time. So he will not reach double the distance covered by the G. If he climbed 30 steps then the escalator also would climb 30 steps in that time, so he would end up 15 steps up in the air 😛
this was really helpful sir
Just one query…what will be the ratio of speeds if person and escalator are moving in opposite direction?
I tried visualizing, but not able to
Thanks in advance
The 2nd question can be solved in a similar logic as the 1st question, of course the alternate method being slightly lengthy but easy to understand.
no more backing off on escalator problems! thank you sir!
Sir, I got a similar question but my answer ain;t matching. Please tell me where I might be going wrong!
1: Raju is walking down an escalator (a moving staircase) with 60 steps which is moving down. From the top, he takes 20 steps to reach the bottom. Find the number of steps that Rajesh, a friend of Raju, would take to reach the bottom, if he starts from the top and walks half as fast as Raju. I did, R/E= 20/80 RJ/E=x/(60+x)
Dividing both, we get 8x=60+x and now troubles arises since x ain;t integer. Where lies the fallacy, Sir?
2: Also, I;d request you to please help me with this question _/\_
A triangle is constructed in the x-y plane, with the vertices of its base lying
on the line x + y = 36, and the third vertex being the origin, such that all the
vertices have integer co-ordinates. How many such triangles can be
constructed, if no portion of the triangle lies outside the first quadrant and
the magnitude of its area is a positive integer?
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