Water is flowing at the rate of 25 km./hr. through a cylindrical pipe of diameter 14 cm. into a rectangular tank which is 50 m. long and 44 m. wide. In how many hours will the water level in the tank raise by 42 cm?
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2 hours
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2.4 hours
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1.8 hours
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3.2 hours
B
Correct answer
Explanation
Volume of water needed = tank area × height rise = 50m × 44m × 0.42m = 924 m³. Pipe cross-section area = π × (0.07m)² × 25km/hr × time. Solving: π × 0.0049 × 25,000 × time = 924. This gives time ≈ 2.4 hours. The key is converting all units consistently (km/hr to m/hr, cm to m).