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At a metro station, a girl walks up a st...

At a metro station, a girl walks up a stationary escalator in time `t_1` If she remains stationary on the escalator, then the escalator take her up in time `t_2`. The time taken by her to walk up the moving escalator will be.

A

`(t_(1)+t_(2))//2`

B

`t_(1)t_(2)//(t_(2)-t_(1))`

C

`t_(1)t_(2)//(t_(2)+t_(1))`

D

`t_(1)-t_(2)`

Text Solution

Verified by Experts

The correct Answer is:
C

velocity of girl `v_(g)=(L)/(t_(1))`
Velocity of escalator `v_(e)=(L)/(t_(2))`
Net velocity of the girl`=v_(g)+v_(e)=(L)/(t_(1))+(L)/(t_(2))`
`(L)/(t)+(L)/(t_(1))+(L)/(t_(2))impliest=(t_(1)t_(2))/(t_(1)+t_(2))`
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Knowledge Check

  • At a metro station, a girl walks up a stationary escalator in time t_(1-) . If she remains stationary on the escalator, then the escalator takes her up in time t_(2) . The time taken by her to walk up on the moving escalator will be :

    A
    `(t_(1)+t_(2))/(2)`
    B
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    C
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    D
    `t_(1)-t_(2)`
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    A
    `(t_1 t_2)/(t_2 - t_1)`
    B
    `(t_1 t_2)/(t_2 + t_1)`
    C
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  • Preeti reached the metro station and found that the escalator was not working. She walked up the stationary escalator in time t_(1) . On other days, if she remains stationary on the moving escalator, then the escalator takes her up in time t_(2) . The time taken by her to walk up on the moving escalator will be:

    A
    `(t_(1)t_(2))/(t_(2)-t_(1))`
    B
    `(t_(1)t_(2))/(t_(2)+t_(1))`
    C
    `t_(2)-t_(1)`
    D
    `(t_(1)+t_(2))/(2)`
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