Infosys Company Numerical Ability Time Distance and Speed

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.

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150
14 years agoHelpfull: Yes(7) No(1)

Let the speed of escalator be u stairs per minute
It is given that B runs down and takes 90 steps in the same time that A takes 10 steps.
Let A takes time t to cover 10 steps; thus time taken by B to cover 90 steps is also B
Now A covers total 50 steps so total time taken by A = 5t

Now equating the distance covered as i previous question
50 + u*5t = 90 + u*t
u*t = 10

So,
Number of steps in the stairs = 90 + u*t or 50 + u*t = 100
14 years agoHelpfull: Yes(6) No(8)
Lets suppose that A walks down 1 step / min and
escalator moves n steps/ min
It is given that A takes 50 steps to reach the bottom
In the same time escalator would have covered 50n steps
So total steps on escalator is 50+50n.

Again it is given that B takes 90 steps to reach the bottom and time
taken by him for this is equal to time taken by A to cover 10 steps i.e
10 minutes. So in this 10 min escalator would have covered 10n steps.
So total steps on escalatro is 90 + 10n

Again equating 50 + 50n = 90 +10n we get n = 1
Hence total no. of steps on escalator is 100.
10 years agoHelpfull: Yes(5) No(0)
100 steps.
14 years agoHelpfull: Yes(2) No(1)
100
14 years agoHelpfull: Yes(1) No(0)
10 steps in t1 sec
90 steps in t1 sec
but we need 50steps 50steps in 5t1 sec

ans= (90*5t1)-(50*t1)/(5t1-t1)
= 400/4
ans =100steps
10 years agoHelpfull: Yes(1) No(0)
what is the correct answer of this question.....150 or 100?
10 years agoHelpfull: Yes(0) No(2)
150 because 100 + 50 = 150
5 years agoHelpfull: Yes(0) No(0)

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