A waste having an ultimate CBOD of 1,000 mg/L is discharged to a river at a rate of 2 m3/s. The river has an ultimate CBOD of 10 mg/L as well as is flowing at a rate of 8 m3/s. Presumptuous a reaction-rate coefficient of 0.1/day, compute the ultimate and 5-day CBOD of the waste at the point of discharge (0 km) and 20 km downstream. The river is sinuous at a velocity of 10 km/day.