Tank 1 initial contains 70 L (liters) of water

Question

and 450 g of salt, while tank 2 initially contains 20 L of water
and 200 g of salt. Water containing 10 g/L of salt
is poured into tank1 at a rate of 1 L/min while the mixture
flowing into tank 2 contains a salt concentration of 50 g/L
of salt and is flowing at the rate of 4 L/min.
The two connecting tubes have a flow rate of 4 L/min from
tank 1 to tank 2; and of 3 L/min from tank 2 back to tank 1.
Tank 2 is drained at the rate of 5 L/min.

how do you find q'(t)?
how do you find the initial values of p and q?

Answer 1

13

Answer 2

R{in}-R{out}=dA/dt, R=rate
Initial values are initial amounts of salt.