The density of population over 40 hectares is 250/hectare. If water supply demand per day is 200 litres and sewage discharge is 80% of water supply, the sewage flow in sewers of separate system, is A. 0.05552 cumec B. 0.05554 cumec C. 0.05556 cumec D. 0.0556 cumec

The correct answer is A. 0.05552 cumec.

The density of population is 250 people per hectare. The area is 40 hectares. Therefore, the total population is 250*40 = 10000 people.

The water supply demand per day is 200 litres per person. Therefore, the total water supply demand is 200*10000 = 2000000 litres per day.

The sewage discharge is 80% of the water supply. Therefore, the sewage discharge is 0.8*2000000 = 1600000 litres per day.

The sewage flow in sewers of separate system is 1600000/86400 = 0.05552 cumec.

Here is a brief explanation of each option:

• Option A: 0.05552 cumec. This is the correct answer.
• Option B: 0.05554 cumec. This is the closest answer to the correct answer, but it is still wrong.
• Option C: 0.05556 cumec. This is also a close answer, but it is still wrong.
• Option D: 0.0556 cumec. This is the most wrong answer.