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Bunuel
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An escalator is descending at constant speed. A walks down and takes 5 24 Dec 2020, 05:52
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C
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95% (hard)

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42% (02:13) correct 58% (02:10) wrong based on 137 sessions

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An escalator is descending at constant speed. A walks down and takes 50 steps to reach the bottom. B runs down and takes 90 steps in the same time as A takes 10 steps. How many steps are visible when the escalator is not operating?

A. 90
B. 95
C. 100
D. 105
E. 150
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C
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An escalator is descending at constant speed. A walks down and takes 5 24 Dec 2020, 06:57
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\(50 + 50x = 90 + 10x => x = 1\)

No of the steps in the escalator \(90+10*1=100\)

IMO Ans C
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An escalator is descending at constant speed. A walks down and takes 5 25 Dec 2020, 00:14
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Bunuel
An escalator is descending at constant speed. A walks down and takes 50 steps to reach the bottom. B runs down and takes 90 steps in the same time as A takes 10 steps. How many steps are visible when the escalator is not operating?

A. 90
B. 95
C. 100
D. 105
E. 150
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B runs down and takes 90 steps to reach the bottom, the time B took was 1/5 of the time A took. Hence A took 5 times as much time as B. We may set the number of steps the escalator traveled for A as 5x, and the number of steps the escalator traveled for B as x. Then we have the equation 50 + 5*x = 90 + x, and x = 10. Then 50 + 5x = 100 steps total.

Ans: C
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An escalator is descending at constant speed. A walks down and takes 5 25 Dec 2020, 21:29
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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. :)
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An escalator is descending at constant speed. A walks down and takes 5 25 Dec 2020, 23:51
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Bunuel
An escalator is descending at constant speed. A walks down and takes 50 steps to reach the bottom. B runs down and takes 90 steps in the same time as A takes 10 steps. How many steps are visible when the escalator is not operating?

A. 90
B. 95
C. 100
D. 105
E. 150
Show more


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
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An escalator is descending at constant speed. A walks down and takes 5 20 Jul 2022, 07:03
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I don't get the 1/5 ratio here - can someone explain please?
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An escalator is descending at constant speed. A walks down and takes 5 01 Jul 2023, 06:45
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azamatboden
I don't get the 1/5 ratio here - can someone explain please?
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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.
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An escalator is descending at constant speed. A walks down and takes 5 07 Mar 2025, 11:22
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