At a metro station, a girl walks up a stationaryescalator 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 on the moving escalator will be-

Options

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)`

Answer

3

Explanation

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