Multiple choice

The water in a rectangular reservoir having a base 90 m by 50 m is 4.5 m deep. In what time can the water be emptied by a pipe of which the cross-section is a square of side 24 cm, if the water runs through the pipe at the rate of 9 km per hour? एक आयताकार जलाशय में पानी जिसका आधार 90 मीटर गुणा 50 मीटर है, 4.5 मीटर गहरा है। यदि पाइप से पानी 9 किमी प्रति घंटे की दर से बहता है, तो 24 सेमी भुजा वाले एक वर्ग के पाइप से पानी कितने समय में खाली किया जा सकता है?

  1. 40 hrs. 40 घंटे

  2. 58hrs. 58 घंटे

  3. 54hrs. 54 घंटे

  4. 52 hrs. 52 घंटे

  5. None of these इनमें से कोई नहीं
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Volume of reservoir = 90 × 50 × 4.5 = 20250 m³. Cross-sectional area of pipe = 24 × 24 = 576 cm² = 0.0576 m². Water flow speed = 9 km/hr = 9000 m/hr. Flow rate = area × speed = 0.0576 × 9000 = 518.4 m³/hr. Time to empty = 20250 / 518.4 = 39.06 hours ≈ 39 hours, which is not listed in options A-D. Therefore E (None of these) is correct.

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