Question

Ruma reached the metro station and found that the escalator was not working. She walked up the stationary escalator with velocity \( v_1 \) in time \( t_1 \). On another day if she remains stationary on the escalator moving with velocity \( v_2 \), then the escalator takes her up in time \( t_2 \). The time taken by her to walk up with velocity \( v_1 \) on the moving escalator will be

• A. \( \frac{t_1t_2}{t_2-t_1} \)
• B. \( \frac{t_1t_2}{t_1+t_2} \)
• C. \( \frac{t_1-t_2}{t_1+t_2} \)
• D. \( \frac{t_1+t_2}{2(t_1-t_2)} \)

Hint:

Relative speed problems: \begin{itemize} \item Add speeds when moving together. \item Use common length. \end{itemize}

Answer 1

The Correct Option is B