Question

Two sisters go up 40-step escalators. The older sister rides the up escalator, but can only take 10 steps up during the ride since it is quite crowded. The younger sister runs up the empty down escalator, arriving at the top at the same time as her sister. How many steps does the younger sister tak

Answer 1

The options for this question are missing, here are the missing options:

A) 70

B) 60

C) 80

D) 50

E) 90

Answer:

The total number of escalators are 40, so that means the older sister took 30 steps and then she took 10 steps on her own. So in order to match her steps the younger sister must take 70 steps.

S = √ 1 + 1/1² + 1/2² + √1 + 1/2² + 1/3²

We will make the equations like this and will go till √1 + 1/1999² + 1/2000²

Here we will find the value of S

1999 x 2000/2001

2000 x 2001/1999

1999 x 2001/2000

1999/2000

2001/2000

If there is any confusion please leave a comment below.