Fresh water flows into tank 1; mixed brine flows from tank 1 into tank 2, from tank 2 into tank 3, and out of tank 3; all at the given flow rate r gallons per minute. The initial amounts x1 (0)=xo (lb), and x2(0) = 0, and x3 (0) = 0 of salt in the three tanks are given, as are their volumes V1, V2, and V3. First solve for the amounts of salt in the three tanks at time t, then determine the maximal amount of salt that tank 3 ever contains. Finally, construct a figure showing the graphs of x1(t), x2(t), and x3 (1). r = 48, x0 = 60, V₁ = 12, V₂ = 8, V3 = 24 x₁ (t)= X2(t)= X3(1)=