Speeds of Meena and Tenna are in the ratio 2:3 for the same distance A→B. Meena takes 20 minutes more than Tenna for A→B. If Meena doubled her speed, how long would she take for A→B (in minutes)?

Difficulty: Easy

Correct Answer: 30 min

Explanation:

Introduction / Context:Let speeds be 2k and 3k for Meena and Tenna; let distance be D. Time is distance/speed. Use the 20-minute difference to find D/k, then compute Meena’s time if she doubles her speed to 4k.

Given Data / Assumptions:

  • Speed ratio 2:3 (Meena:Tenna).
  • Time difference = 20 min = 1/3 h.

Concept / Approach:t_M − t_T = D/(2k) − D/(3k) = D/(6k) = 1/3 ⇒ D/k = 2. Then doubled-speed time = D/(4k) = (D/k)/4.

Step-by-Step Solution:

D/k = 2.New time = (D/k)/4 = 2/4 = 1/2 h = 30 min.

Verification / Alternative check:Original times: D/(2k) = 1 h; D/(3k) = 2/3 h; difference 1/3 h = 20 min (consistent when D/k = 2).

Why Other Options Are Wrong:60/45/110 min do not match the derived new-time expression.

Common Pitfalls:Applying the 2:3 ratio to times instead of speeds (times are inversely proportional).

Final Answer:30 min

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