ANS:C - 0.05556 cumec

To find the sewage flow in sewers of a separate system, we need to follow these steps:

1. Calculate the total water supply demand per day:

Water supply demand=Population×Water demand per capitaWater supply demand=Population×Water demand per capita Given that the population density is 250/hectare and the area is 40 hectares: Population=250 people/hectare×40 hectares=10000 peoplePopulation=250people/hectare×40hectares=10000people So, the total water supply demand per day is: Water supply demand=10000 people×200 litres/person/day=2000000 litres/dayWater supply demand=10000people×200litres/person/day=2000000litres/day

2. Calculate the sewage discharge: Given that sewage discharge is 80% of water supply, the sewage discharge is:

Sewage discharge=0.80×2000000 litres/day=1600000 litres/daySewage discharge=0.80×2000000litres/day=1600000litres/day

3. Convert the sewage discharge from litres per day to cubic meters per second (cumec):

1 cumec=1000 litres/second1cumec=1000litres/second So, to convert litres/day to cumec, we divide by 8640086400 (the number of seconds in a day) and then by 10001000: Sewage flow (cumec)=1600000 litres/day86400 seconds/day×1000≈0.0185185 cumecSewage flow (cumec)=86400seconds/day×10001600000litres/day​≈0.0185185cumec Given the options provided, none of them exactly matches the calculated value. It seems there might be a discrepancy in the calculations or the options provided. You may want to review the problem or the options to ensure accuracy.