Two rooftop cisterns supply a tropical bungalow with shower water. The water surface in the uppermost cistern (A) is 8 m above the ground, and the water surface in the lower cistern (B) is 7 m above the ground. They both supply water to a junction below the lowest cistern's water surface through 3-cm PVC tubes (n = 0.011). Each tube is 2 m long. A 5-m supply line leads from the junction through another 3-cm PVC tube to a pan shower (essentially a reservoir with holes in the bottom) 3 m above the ground. What flow rate can be expected in the shower in liters per second?