Water flows in a tank 150 m × 100 m at the base through a pipe w...
Understanding the Problem
To determine how long it will take for the water in the tank to reach a depth of 3 meters, we need to calculate the volume of water required and the volume flow rate through the pipe.
Tank and Water Volume
- The dimensions of the tank are 150 m × 100 m.
- The required depth of water is 3 m.
Calculating the Volume of Water Needed
- Volume of water (V) = length × width × height
- V = 150 m × 100 m × 3 m = 45,000 cubic meters.
Pipe Cross-Section and Flow Speed
- The cross-section of the pipe is 2 dm × 1.5 dm, which converts to meters as:
- 2 dm = 0.2 m
- 1.5 dm = 0.15 m
- Cross-sectional area (A) = 0.2 m × 0.15 m = 0.03 square meters.
Flow Rate Calculation
- Speed of water flow = 15 km/h = 15,000 m/3600 s = 4.167 m/s.
- Flow rate (Q) = Area × Speed = 0.03 m² × 4.167 m/s = 0.125 m³/s.
Time Required to Fill the Tank
- To find the time (t) to fill 45,000 m³, we use the formula:
- t = Volume / Flow Rate = 45,000 m³ / 0.125 m³/s = 360,000 seconds.
Convert Time to Hours
- Convert seconds to hours:
- 360,000 seconds ÷ 3600 seconds/hour = 100 hours.
Conclusion
The time required for the water to reach a depth of 3 meters in the tank is 100 hours, making option 'A' the correct answer.
Water flows in a tank 150 m × 100 m at the base through a pipe w...
The volume of water in the tank
= 150 × 100 × 3 = 45000 m
3Area of a cross-section of the pipe
= 2dm × 1.5dm

Let the time taken be t hours.
The volume of water that flows in a tank in t hours.

= 450 t m
3⇒ 450t = 45000
⇒ t = 45000/450 = 100 hours