Question

Two sisters Neha and Monica walk to school from the house. Neha takes 40 minutes while Monica takes 30 minutes. One day Neha started 5 minutes earlier than Monica. In how many minutes would Monica overtake Neha?

Accepted Answer

B. Ratio of time taken = 40 : 30 = 4 : 3. Since distance is constant, ratio of speeds = 3 : 4. Let Neha's speed be $3v$ and Monica's speed be $4v$. In 5 minutes, Neha covers a distance of $3v 	imes 5 = 15v$. Relative speed of Monica with respect to Neha = $4v - 3v = v$. Time required for Monica to overtake Neha = $\frac{	ext{Initial distance}}{	ext{Relative speed}} = \frac{15v}{v} = 15$ minutes.

Neha and Monica walking to school

Explanation

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