A tank contains 60 kg of salt and 2000 L of water. Water containing 0.8kgL of salt enters the tank at the rate 8 L/min. The solution is mixed and drains from the tank at the rate 2 L/min. A(t) is the amount of salt in the tank at time t measured in kilograms.
A(0) = 60(kg)


A'+2A/(2000+6t)-6.4=0


The integrating factor is = e^(1/3ln|2000+6t|)


So what is the A(t) = ?kg