River A has a flow rate of 3.0 m^3/sec. Stream B discharges into the river at a flow rate of 0.05 m^3/sec. to study mixing of the stream and river, a conservative tracer is to be added to stream B. the instruments that measure the tracer can detect a concentration of 1.0 mg/L. what minimum tracer concentration (mg/L) must be achieved in Stream B so that 1.0 mg/L of the tracer can be measured after the river and stream mix? what mass rate of tracer (kg/day) must be added to Stream B to achieve this concentration