The dilution factor (P) for an unseeded mixture of waste and water is 0.030. The DO of the mixture is initially 9.0 mg/L, and after 5 days, it has dropped

to 3.0 mg/L. The reaction rate constant (k) has been found to be 0.22 day-1. What would be theremaining BOD (in mg/L) after 5 days?