Department of Mathematics & Statistics Prof. Champak D. Panchal

Department of Mathematics & Statistics Prof. Champak D. Panchal

MAP 2302, QUIZ 5, NAME ______, ______03/02/04

1. (5 pts): Suppose a brine containing 0.3 kg of salt per Liter runs into a tank initially filled with 400 Liter of water containing 2 kg of salt. If the brine enters at 10 L/min, the mixture is kept uniform by stirring, and the mixture flows out at the same rate, find the mass of salt in the tank after 10 minutes.

Hint: Let A(t) denote the # of kgs of salt in the tank at time t after the process begins.

2. (5 pts): A 200-gallon tank is half full of distilled water. At time t = 0, a solution containing 0.5 pound of concentrate per gallon enters the tank at the rate of 5 gallons per minute, and the well stirred mixture is withdrawn at the rate of 3 gallons per minute.

At the time the tank is full, how many pounds of concentrate will it contain?

Hint: Let A(t) denote the # of pounds of concentrate in the tank at time t.