Problems 31 through 34 deal with the open three-tank system of fig. 5.2.2. fresh water flows into tank 1: mixed brine flows from tank i 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 x_1 (0) = x_0 (lb), x_2(0) = 0, and x_3(0) = 0 of salt in the three tanks are given, as are their volumes v_1, v_2, and v_3 (in gallons), 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 x_1(t), x_2(t), x_3(t). r = 30, x_0 = 27, v_1 = 30, v_2 = 15, v_3 = 10 r = 60, x_0 = 45, v_1 = 20, v_2 = 30, v_3 = 60