An escalator is descending at constant speed. A walks down and takes 5

chetansharma Could you please help with this one ? Im not getting the logic of this question. Please help with a detailed solution.


Best !!!

Steps travelled by A = Steps travelled by B

50+ 5*x = 90 + x (as B takes 5 times less time)
So, 4*x= 40, x= 10
Total steps = 90 +10 = 100

I think C.

ShankSouljaBoi, the question misses out on mentioning that B has reached the bottom in 90steps. It just mentions that B takes 90 steps in the time A takes 10 steps. And that is a big issue!

So, say the question meant that B reaches the bottom in 90 steps, and in the same time as A takes 10 steps. Since A takes 50 steps to reach bottom and the speed of escalator is constant, we can say A will take 1/5 of total time to take 10 steps. This further means that B reaches the bottom in 1/5 th time taken by A.

Now let the speed of escalator be such that it covers x steps in the time A takes 10 steps, so in terms of B the number of steps = 90+x, while in terms of A, the number of steps = \(50+(\frac{50}{10})*x=50+5x\)
=> \(90+x=50+5x....x=10\)
steps = 90+10=100

C

That's why I cdnt form the equation. So crystal clear now thank you so much chetansharma

Posted from my mobile device

I don't get the 1/5 ratio here - can someone explain please?

Hi
The following explanation might help those with the quoted doubt.

So, A is known to take 10 steps when B takes 90 steps. Lets assume this happens at a time t.
i.e, A takes 1 step in t/10 seconds.
so, A takes its 50 steps in (50t)/10=5t seconds.