Multiple choice

A tank gets empty in 4 hours due to a leak in it. A pipe fills water at the rate of 3 litres per minute. When the tank is full, the inlet is opened and due to the leak, the tank gets emptied in 6 hours. How many litres can the tank hold?

  1. 720 litres

  2. 2160 litres

  3. 2960 litres

  4. 920 litres

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Leak empties in 4 hours (rate = 1/4). With inlet, it empties in 6 hours (rate = 1/6). Inlet rate = 1/4 - 1/6 = 1/12. If inlet fills 3 liters/min, it fills 180 liters/hour. Total capacity = 180 * 12 = 2160 liters.

AI explanation

By the Net Work formula, the part of the tank emptied in one hour by the leak and the inlet together is 1/6, while the leak alone empties 1/4 per hour. So the inlet fills 1/4 minus 1/6, giving 1/12 of the tank per hour. Because the inlet supplies 3 litres per minute, or 180 litres per hour, the total capacity is 180 multiplied by 12. The tank holds 2160 litres.

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