Problems on escalators, to be done without pencil, paper and equations 🙂
1. On a stationary escalator, there are 120 steps. P starts from the top to walk down the escalator at the same time as Q starts from the bottom to walk up the escalator. The escalator is a up-going escalator and speed of P is twice the speed of Q. If they meet on 40th step from top (i.e. P is 40 steps from top and Q is 80 steps from bottom), find the ratio of the time taken for P to reach the bottom to that taken by Q to reach the top.
2. When I walk up an escalator, I need to take 20 steps to reach the top. However when I walk down the same escalator, I need to take 60 steps to reach the bottom. Find the number of steps on the escalator.
3. Amit and Bharat start walking up an up-going escalator at the same time. However Amit reaches the top after 60 seconds, whereas Bharat reaches the top after 75 seconds (because their walking speeds are different). If both of them started walking down the same escalator from the top, Amit would take 100 seconds to reach the bottom whereas Bharat would take 150 seconds. In how much time would a stationary man on the escalator cover the total distance?
4. A up-escalator and a staircase are next to each other. In the same time as Amit can walk up and down the staircase twice (i.e. a total of two flights up and two flights down), Bharat can walk up and down the escalator only once (i.e. start from bottom, walk up to the top, start walking down and reach bottom). If the walking speed of Amit and Bharat is the same, find the ratio of their speed to the speed of escalator.
5. A down-escalator and a staircase are next to each other. Starting from the bottom, if I walk up the escalator, I would be only mid-way in the time I would have reached the top had I taken the staircase. Starting from the top, if I walk down the staircase, what fraction of distance would I have covered in the time it would have taken me to reach the bottom had I walked down the escalator?
Discuss the solutions in the comments. Strive for a non-mathematical solution, something that you can work in your heads only, rather than using pencil & paper. Such solutions will be posted in a day or so.
Update: Solutions have been uploaded here.
hiii ,i want to join coaching for cat
Dear Chandra sir,
I have been following your videos as well as other teachers’ videos from Takshzila for around last 4 months at YouTube. Many of them are around an year old and some videos at Takshzila’s channel are just a few weeks old. All of them are great.
But there are few topics for which there is a requirement of detailed video lectures, like Escalators; 2 boats in water; Circular tracks; multiple to-fro running problems, etc..
Other topics (apart from Speed, Distance, Time) for which videos are required include:
1. Trigonometry (Heights and Distances); as I saw some questions in XAT extremely tough from this topic.
2. Special Equations (finding number of solutions for 1 equation in 2 or 3 variables).
3. Mensuration of plane figures (like ratio of area of hexagon to inscribed triangle/rectangle).
4. Games and Tournament (Grand Slam tournaments; Knockout stages; coin collection/picking problems).
5. Reasoning based DI (Reasoning + Data Interpretation).
With CAT 2015 date to be announced in just a couple of days and CAT exam itself in about next 3 months, I am very worried. Please let me know where can I find above topics’ videos, and whether they would be uploaded on YouTube in coming weeks.
Thanks and Regards,
Amit
Plz explain how to do dese without pen paper nd equations…
solutions uploaded. See new post.
Your approach plz!
Tomorrow
Solutions uploaded. See new post.
1. 2:1
2. 30
3. 300 sec
4. root of 2
5. 2/3
Great 🙂