Please Help! Homework assigned over the weekend and the tutoring center is close
ID: 2985802 • Letter: P
Question
Please Help! Homework assigned over the weekend and the tutoring center is closed Fri-Sun
A tank initially contains 120 liters of pure water. A salt solutions with concentration of 4 grams/liter of salt enters the tank at a rate of 2 liters/min and the well-stirred mixture leaves the tank at the same rate. Find an expression for the amount of salt in the tank at any time t and the limiting amount of salt in the tank as t rightarrow infinity. Find the time when the concentration reaches 2 grams/liter.Explanation / Answer
amount of salt in the tank at any time t
= flow rate of solution x concentration of solution x time
= 2 liters/min. x 4 grams/liter x t min.
= 8t grams
Final concentraion ( intial volume + flow rate of solution*time ) = flow rate of solution x concentration of solution*time
2 grams/liter ( 120 liter + 2 liters/min.*time ) = 2 liters/min. x 4 grams/liter*time
2 ( 120 + 2*time ) = 2x4*time
240 + 4*time = 8*time
8*time - 4*time = 240
4*time = 240
time = 240/4 = 60 mins.