Explanation:

- Calculate the volume of the tank:

- The tank is hemispherical with a radius of 7 meters.

- Volume of a hemisphere = \((2/3) \times \pi \times r^3\).

- Plug in the radius: \((2/3) \times \pi \times 7^3 \approx 718.4 \, \text{m}^3\).

- Convert the volume to liters:

- 1 m³ = 1000 liters, so 718.4 m³ = 718,400 liters.

- Calculate 3/4 of the volume:

- \((3/4) \times 718,400 \approx 538,800 \, \text{liters}\).

- Determine time to empty 538,800 liters at 15.4 liters/sec:

- Time = Total volume / Rate = 538,800 / 15.4 seconds.

- Time ˜ 35,000 seconds.

- Convert seconds to hours:

- 1 hour = 3600 seconds.

- Time = 35,000 / 3600 ˜ 350/36 ˜ 175/18 hours.

- Check options for correct match:

- ?? Option 1: 175/18 hours is the match.

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