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CUET · MATHS · PYQ PAPER 2025

Two pipes A and B can fill a tank respectively in 30 min and 45 min.
Both A and B are opened together for some time and then pipe B is turned off.
If the tank is completely filled in 20 min, find after how many minutes pipe B is turned off.

  1. A 5 min
  2. B 30 min
  3. C 15 min
  4. D 25 min
Verified Solution

Answer & Solution

Correct Answer

(C) 15 min

Step-by-step Solution

Detailed explanation

\( \frac{20}{30} + \frac{t}{45} = 1 \) \( \frac{2}{3} + \frac{t}{45} = 1 \) \( \frac{t}{45} = 1 - \frac{2}{3} \) \( \frac{t}{45} = \frac{1}{3} \) \( t = 15 \) min