Suppose that a large mixing tank initially holds 1000 L of water in which 25 kg of salt have been dissolved. Another brine solution is pumped into the tank at a rate of 10 L/min, and when the solution is well stirred, it is then pumped out at a slower rate of 7.5 L/min. If the concentration of the solution entering is 0.55 kg/L, determine a differential equation for the amount of salt A(t) in the tank at time t>0. (Use A for A(t).)
dA/dt=___ kg/min
A=
[2 2 2 0 0 0 0 0 0 0 0]
[4 2 0 0 0 0 0 0 0 0 0]
[6 4 2 0 0 0 0 0 0 0 0]
[0 0 0 1 3 0 0 0 0 0 0]
[0 0 0 1 5 0 0 0 0 0 0]
[0 0 0 0 0 3 3 3 0 0 0]
[0 0 0 0 0 0 3 3 0 0 0]
[0 0 0 0 0 0 0 3 0 0 0]
[0 0 0 0 0 0 0 0 2 0 0]
[0 0 0 0 0 0 0 0 0 2 1]
[0 0 0 0 0 0 0 0 0 1 2]